NOVELTY - Increasing growth speed of Ganoderma lucidum mycelia and the liquid fermentation biomass comprises taking G. lucidum as strain, activating by potato dextrose agar medium, performing liquid shake flask cultivation, performing enzyme hydrolysis of G. lucidum mycelium, shaking to obtain the protoplast, performing mutagenesis of G. lucidum protoplast, selecting fast growth, regenerating white mycelium colonies by peanut meal slant medium, and inculcating peanut meal submerged fermentation culture medium to obtain biomass, polysaccharides, and triterpenoids.    USE - The method is useful for increasing growth speed of G. lucidum mycelia and the liquid fermentation biomass (claimed).    ADVANTAGE - The method obtains G. lucidum strain with high mycelial growth speed and high biomass through induced mutation for the first time; adopts slant culture medium for the peanut meal, which is more favorable for quick growth of the G. lucidum mycelia in comparison with a slant culture medium for potato dextrose agar; and adopts the liquid fermentation culture medium for the peanut meal which is more favorable for acquisition of higher biomass.    DETAILED DESCRIPTION - Increasing growth speed of Ganoderma lucidum mycelia and the liquid fermentation biomass comprises taking Ganoderma lucidum as strain, activating by potato dextrose agar medium, performing liquid shake flask cultivation, performing enzyme hydrolysis of G. lucidum mycelium, shaking at 28-32 degrees C for 1.5-4 hours to obtain the protoplast, adopting nitrite as a mutagen for mutagenesis of G. lucidum protoplast, selecting fast growth, regenerating white mycelium colonies by peanut meal slant medium, and inculcating peanut meal submerged fermentation culture medium to obtain biomass, polysaccharides, and triterpenoids, where the method specifically comprises: (i) preparing potato dextrose agar slant culture: adopting strain according to GB4789.15-2010 'microbiological examination of food hygiene molds and yeasts' preparation; (ii) activating strain: inoculating G. lucidum strain No. 5.786 on potato dextrose agar slant medium and activating for 1-2 seconds; (iii) taking liquid culture mycelium, collecting mycelium pellet by filtration, washing with sterile water for 2-3 times, then rinsing with mannitol for 2-3 times, transferring into mercaptoethanol, oscillating in a constant temperature shaker for 30-60 minutes, collecting mycelial pellets by filtration, washing with mannitol for 2-3 times, centrifuging the precipitate to obtain mycelium, adding mycelium into enzyme solution taken in the ratio of 1:10-20, performing enzymolysis by oscillating at constant temperature for 2-4 hours, filtering, centrifuging the filtrate at 500-1000 revolutions per minute for 3-5 minutes, centrifuging the supernatant at 3000-4000 revolutions per minute for 5-10 minutes, and collecting the precipitated protoplasts, rinsing with mannitol and diluting the protoplasts 10-15 times with 0.9% saline; (iv) adding 0.06 mol/l sodium nitrite and 1 mol/l acetate buffer into the diluted protoplast solution, constantly treating at 27 degrees C for 5-25 minutes, adding twice the volume of acetate buffer, terminating mutagenesis by 0.7 mol/l disodium hydrogen phosphate (pH 8.6) solution, at applying the mutagenized protoplasts to the regeneration medium, and culturing at 27 degrees C for 5 days; (v) allowing fast growth, and inoculating mycelium white colonies into peanut meal slant medium, where the medium consists 10-30 g/l corn, 2-5 g/l peanut meal, 1-3 g/l potassium dihydrogen phosphate, 0.5-1.5 g/l magnesium sulfate heptahydrate, 0.3-0.8 g/l vitamin B2 and 20 g/l agar, culturing at 27 degrees C for 6-7 days to obtain first generation of mutant strains, inoculating into fresh peanut meal slant medium, culturing at 27 degrees C for 6-7 days to obtain second generation of mutant strains, and by the same method obtaining third generation-ninth generation strains; (vi) inoculating first, third, fifth, seventh, and ninth generation strains into peanut meal submerged fermentation medium, where the medium consists 10-30 g/l corn, 2-5 g/l peanut meal, 1-3 g/l peptone, 10-30 g/l glucose, 1-3 g/l yeast extract, 1-3 g/l potassium dihydrogen phosphate, 0.5-1.5 g/l magnesium sulfate heptahydrate, pH 6.5, and culturing at 27 degrees C for 5-7 days; (vii) separating biomass: filtering the fermentation broth to collect mycelium, and at 60 degrees C, drying to constant mass; (viii) extracting intracellular polysaccharides: taking 1 g dried mycelium, adding 10 volumes of distilled water, placing in 90 degrees C water bath for 2-3 hours, centrifuging at 4000 revolutions per minute for 5-10 minutes, collecting the supernatant, repeating precipitate extraction two times, combining the supernatant of three times, concentrating in 80-90 degrees C water bath to the original volume of 0.2-0.25 times, adding 4-5 times the volume of 95% ethanol, allowing to stand at 4 degrees C, centrifuging the concentrate, washing the precipitate twice with ethanol, and drying to constant weight to obtain intracellular polysaccharides; (ix) extracting intracellular triterpenoids: : taking 1 g dried mycelium, add 50 ml methanol, allowing to stand overnight and then filtering, evaporating to dryness, and dissolving in 4 ml 95% ethanol solution; (x) placing the mutant strain in paraffin oil or sandy soil tube, storing at 4 degrees C, and passaging once per year.