Abstract: The biodegradability performance and several influencing factors of polyepoxysuccinic acid were studied.The influencing factors are the proportion of nitrogen and phosphorus,concentration of PESA,the time and temperature of biodegradability,oxygen of solution.The degradation ratio reaches to 73.7% under C∶N∶P 100∶20∶1,temperature 20 ℃,time 28 d,enough oxygen of solution,and 5 mg·L~(-1)of PESA.The biodegradability of polyepoxysuccinic acid is easier than else according to OECD301B standard.