In order to improve the quality of the environment as well as its purification capacity, to reduce environmental costs and achieve clean and efficient management of malodorous gas pollution, on the basis of fully understanding the theory of biotechnology, this paper presents the research of biotechnology to control the pollution of malodorous pollutants. In this research, the biofiltration method was used to control the odour gas ammonia produced in waste composting, which can effectively purify gases, with a high ammonia removal rate. One week after the ammonia removal experiment, the removal rate was detected to be around 79.3 %. Twenty-four days after the experiment, the removal rate stabilized at around 98 %. Through the test of pH value of nutrient solution, it was found that the change in pH value corresponded to the increase in removal rate. There are many advantages of applying biotechnology to filter malodorous polluted gases, such as low energy consumption, high degree of purification, good environmental compatibility, simple operation and maintenance, and no secondary pollution. Therefore, it has good application prospects.