Bio-organic fertilizer is an organic combination of traditional organic fertilizer and bacterial fertilizer.It is of great practical value to study the effects of lactic acid and citric acid on the quality of bio-organic fertilizer during its preservation. The results showed that after adding lactic atid and citric acid，the quality of bio-organic fertilizer could still meet the requirements of Chinese bio-organic fertilizer standard( NY 884-2012) after 6 months，and the number of viable bacteria is 60 million and 80 million CFU/g，respectively.The number of viable bacteria in the CK treatment organic fertilizer at the end of the fifth month was only 0.1 million CFU/g，which was lower than the standard 20 million CFU/g.Compared with lactic acid， the addition of citric acid was more beneficial to improve the quality of bio-organic fertilizer during storage， and the contents of nitrogen， phosphorus and small molecular organic amino acids were higher than that of lactic acid by 5.76 mg/g and 128.95 mg/g， respectively.