NOVELTY - Preparing marsh gas using traditional Chinese medicine residue, comprises e.g. (i) crushing the traditional Chinese medicine residue, adding methanogenic bacteria, adjusting the carbon nitrogen ratio, processing, (ii) using complete mixing type anaerobic digester (continuous-flow stirred-tank reactor (CSTR)) where the process flow is: adjusting the concentration of the traditional Chinese medicine residue, entering CSTR, stirring, continuously reacting, adjusting pH, producing crude marsh gas, and (iii) discharging slurry, carrying out solid-liquid separation, and recycling slurry.    USE - The method is useful for preparing marsh gas using traditional Chinese medicine residue (claimed).    ADVANTAGE - The method requires simple equipment; is convenient to manage; reduces urban residents living dependence on fossil energy and reduces greenhouse gas emission; reduces the straw combustion rate; and improves sustainable utilization of straw in rural land, thus improving the farmers living environment and living standard. The marsh gas does not contain carbon monoxide and toxic gases, and is more beneficial to human health and has significant environmental benefit.    DETAILED DESCRIPTION - Preparing marsh gas using traditional Chinese medicine residue, comprises (i) crushing the traditional Chinese medicine residue to 40 meshes, adding 10% methanogenic bacteria in traditional Chinese medicine residue, adjusting the carbon nitrogen ratio to 20-25:1, processing for 10 days, where the temperature is 53-55 degrees C, (ii) carrying out anaerobic digestion reaction by: using complete mixing type anaerobic digester (continuous-flow stirred-tank reactor (CSTR)) where the process flow is: adjusting the concentration of the traditional Chinese medicine residue TS to 8-13%, entering the CSTR, and mechanically stirring, where the frequency is 50 HZ, the amplitude is 15 revolutions/minute, the temperature is 60 degrees C, continuously reacting throughout the day, adjusting the pH value to 6.5-7.8, producing crude marsh gas in the sealed condition, drawing the marsh gas out from the fermentation tank, and (iii) discharging the fermented biogas slurry from the fermentation tank, carrying out solid-liquid separation, and separating the resulting slurry, which is recycled.