NOVELTY - Producing biogas using lignocellulosic materials, involves: crushing the lignocellulosic materials, adding the crushed lignocellulosic materials into an anaerobic reactor, inoculating an inoculum for carrying out primary fermentation to produce biogas; after a biogas producing peak, taking digestate out, mechanically dewatering, carrying out biological treatment, inoculating a microbial agent, carrying out aerobic fermentation; and then inoculating the inoculum for carrying out secondary anaerobic digestion to produce biogas.    USE - The method is useful for producing biogas using lignocellulosic materials (claimed).    ADVANTAGE - Compared with a technology for producing the biogas through pretreatment of the lignocellulosic materials through microorganism inoculating, the method has the advantages that the biogas producing rate of the lignocellulosic materials can be increased by 27.64-47.89%, the consumption of the microbial agent is reduced by about 50%, the loss of readily decomposable organic matters in the lignocellulosic materials in a biotreatment process is greatly reduced, and the accumulated biogas production yield of the lignocellulosic materials is increased by 21.77-41-32% compared with that in the biological pretreatment.    DETAILED DESCRIPTION - Producing biogas using lignocellulosic materials, involves: (a) chopping the lignocellulosic material to not more than 5 cm small pieces; (b) adding the chopped ingredients to an anaerobic reactor fermentation vessel, inoculating in the fermentation inoculum, the inoculum quantity is 5-30% dry weight, mixing and inoculating; (c) adding water to the anaerobic reactor, the reactor in the fermentation initial dry mass concentration is adjusted to 3-30%, sealing the reactor, carrying out a secondary anaerobic fermentation of marsh gas, where the temperature is 15 degrees C; (d) after subjecting to a peak gas production of anaerobic fermentation period, taking out the first anaerobic fermentation gas from the reactor, dehydrating till the water content is 60-75%; (e) carrying out biological treatment, inoculating a microbial agent containing one or more of white rot fungi, Monilinia fructicola and peurotoid fungi, under the conditions of inoculum size being 1-3%, water content being 55-75% and temperature being 20-35 degrees C, carrying out aerobic fermentation for 2-7 days; and (f) then inoculating the inoculum for carrying out secondary anaerobic digestion, where the pH value is 6.9-7.1 and where the reaction temperature is 15-60 degrees C, to produce biogas.