[Background] In view of the high mortality of live pigs due to diseases in China,it is particularly important to establish an efficient harmless method for treating diseased pig carcasses.[Objective] In order to improve the harmless treatment efficiency of compost on diseased pig carcasses.[Methods] We screened out the strains with protein and fat degradation functions and formulated the compound bacterial agents.Single factor experiments and response surface method were employed to optimize the strain ratio and degradation conditions.The degradation performance of compound bacterial agents on diseased pig carcasses and sawdust compost were evaluated.[Results] Strain DB1 was identified as Serratia marcescens with a protease activity of 36.76 U/mL and a degradation rate of 72.17% for pig carcass.Strain ZF2 was Bacillus velezensis,with a lipase activity of 12.33 U/mL and a degradation rate of 70.83% for pig carcass.The optimal ratio of DB1 to ZF2 in compound bacterial agent was 2.55:1,and the optimal degradation conditions obtained by response surface optimization were as follows:temperature at 31.65℃,inoculation amount of 3.11%,pH 6.0,salinity of 0.75%,and Mn²⁺ concentration of 1 mmol/L.A degradation test was carried out under the optimum conditions,which showed a degradation rate of 90.61% after 7 days.The composting test showed that the peak temperature of compost in the control group and the low-,medium-,and high-amount inoculation groups could reach 60,64,69,and 62℃,respectively.The group with an inoculation amount of 3% had the best treatment performance,with the high temperature period lasting for 19 days and the carcass degradation rate of 98.06%.All the indicators of this group were superior to those of the control group (p<0.01).[Conclusion] In this study,we designed the degradation test according to the fat/lean ratio of pig carcass for the first time to evaluate the performance of functional bacteria,which was superior to the previous methods.Taking the degradation rate as the evaluation index,we optimized the strain ratio of functional bacteria.Compared with those in previous studies,the compound bacterial agent designed in this study can well accelerate the temperature rise of composting and the degradation of pig carcass.