Abstract: In order to investigate the effects of reducing irrigation and chemical fertilizers on soil nitrate reductase activities and nitrate content in a facility vegetable field in Mollisols region, in a long-term experiment of Mollisols vegetable field with three treatments: regular irrigation and chemical fertilizers(WF), 80% regular chemical fertilizers + regular irrigation(W80%F), regular chemical fertilizers + 80% regular irrigation(80%WF), we analyzed the changes of soil nitrate reductase activities and nitrate content in eggplant field after reducing irrigation and chemical fertilizers.The results showed that: both reducing irrigation and chemical fertilizers significantly affected soil nitrate reductase activities.Compared to WF, W80%F increased the soil nitrate reductase activities in 0~20 cm and 40~60 cm soil depth by 22.0% and 33.2% respectively, while 80%WF decreased the activities by 5.37% and 23.7% respectively.Soil nitrate reductase activities decreased firstly and then increased with the extension of eggplant growth period.Soil nitrate reductase activities in W80%F and 80%WF at seedling stage and initial fruit stage were significantly higher than that in WF(P < 0.05).Soil nitrate contents in all three treatments decreased with increasing soil depth and exhibited an order of WF>W80% F>80% WF in the same soil depth.Compared with WF, W80%F reduced nitrate contents by 7.91%~31.6% during the whole eggplant growth period; 80%WF increased soil nitrate contents in seedling stage and seedling pulling stage by 9.49% and 13.5% respectively, but significantly reduced the soil nitrate contents in initial and full fruit stage by 69.6% and 54.2% respectively.The correlation analysis between nitrate reductase activity and soil nitrate content showed a significant positive correlation in 40~60 cm soil depth, but no significant correlation in 0~20 cm and 20~40 cm soil depth, indicating that the nitrate reductase activities in deeper soil reflect the changes of soil nitrate content.