Abstract: [Objective]In order to release the nutrient elements of solution sustainablely and controllably , improve plant nutrition liquid fertilizer and hydroponic crop yields, reduce the cost of hydroponic, a new fertilizer synergist-polyaspartic acid (PASP) was added to the plant nutrition solution, investigating the effects on the growth of hydroponic plants.[Method]Using hydroponic nutrient film technique (NEF) and the balanced nutrient solution formula as the blank control group,hydroponic nutrient solution and green-house soilless culture expansion tests were conducted on Chinese cabbage and celery with different polyaspartic acid(PASP) dosages. [Result]The results showed that the nutrition solution with a certain amount of PASP had great effects on the growth of Chinese cabbage and celery, and could well reduce the content of nitrate in vegetable hydroponics. Drying weight of 30d-cultivated hydroponic cabbage in the laboratory increased 9.51 %. Compared with the control group, nitrate content decreased 50.93 %; VC content has an increase of 1.86 times. Celery’s wet weight per plant increased 45.07% and dry weight per plant increased 46.29 %. Nitrate content, compared with the control group ,dropped by 29.94 %, VC content is 1.27 times of the control group. The wet weight of green-house hydroponic celery 30d-cultivated increased 8.5 % and the dry weight increased by 19.5 %. [Conclusion]The solution with a certain amount of PASP will increase the production of hydroponic vegetables and improve the quality of vegetables. A large number of experments showed that 1.5 % PASP is the best dosage.