At present, microbial degradation of garden waste has attracted widespread attention. However, due to the complex and irregular structure of lignin in garden waste, cellulose molecules are embedded in it, forming a natural barrier, which makes it difficult for enzymes to contact with cellulose molecules, leading to decreased decomposability . This study creatively proposed the mixture of two bacteria (white rot fungi and Trichoderma) to decompose garden waste, explore the optimal mixed fermentation conditions and apply them to waste heap rot. Then analyze the law of their physical and chemical properties, mix the organic matter and peat in different proportions for horticultural plant cultivation. Finally evaluate the growth and physiological indexes of the plants after 30 days of culture. The results showed that inoculation of white rot fungi 3d in mixed fermentation could significantly improve the decomposition rate. Meanwhile, response surface analysis on the basis of single factor showed that the decomposition rates of lignin cellulose reached 28.37% and 31.56%, respectively, under the optimal fermentation conditions of 60% water content, 15% total bacteria and 1:2 bacteria. In the rot heap experiment, compared with the other treatment groups, the cultivation substrate with bacterial heap rot product =5:3:2 could increase the chlorophyll content of plants and enhance the photosynthetic efficiency. In addition, under this ratio, the enzyme activities of SOD, POD and CAT in plants were increased by 27.63%, 14.83% and 40.17%, respectively, compared with CK group, which significantly improved the plant stress resistance. To sum up, mixed fungi can solve the problem of garden waste disposal, and the products can be better used in crop cultivation when used together with peat. It has certain practical significance for the harmless resource utilization of waste and the protection of peat and other resources, so as to promote the construction of ecological civilization and sustainable development of the environment.