A pot experiment was carried out to evaluate the effects of supplying different rate of NH + 4 -N/NO- 3 -N fertiliz- ers on the growth， tubers yield and quality of potato under drip fertigation system. The results obtained were as follows: Un- der this experiment condition， biomasses of potato were no different among the five treatments in NH+4-N/NO -3-N ratio. NH+4-N fertilizer could improve N concentration and NO-3-N fertilizer could improve Ca concentration in potato tuber. The content of starch， dry matter and ash had no difference among the five treatments in NH+4-N/NO- 3-N ratio. There had no significant effects on increasing potato tubers yield among the different nitrogen fertilizer treatments， and the commodity rate was the highest in treatment 50/50 in NH+4-N/NO-3-N ratio， the data as 92.01%.