A field experiment was conducted to study the effects of different nitrogen (N) fertilizer rates on growth, yield and economic benefit of winter potato with drip irrigation under mulch and to put forward the appropriate rate of N fertilizer in winter potato production. The results showed that under the condition of drip irrigation under mulch, with the increase of N application rate, the growth period of potato was prolonged while the leaf area index of potato and the number of tubers per plant, potato weight per plant and tuber yield increased first and then decreased, all of which were the highest at N application rate of 345 kg/hm², and the plant height and large tuber weight were both higher than those of other treatments. The emergence rate of potato changed little when N application rate ranged from 0-420 kg/hm², while the emergence rate and tuber yield of potato decreased significantly when N application rate reached 495 kg/hm². Benefit and net income of N application, input-output ratio and agronomic efficiency of N fertilizer increased with the increase of N application rate in the range of 195-345 kg/hm², but decreased gradually when nitrogen application rate was beyond 345 kg/hm², and reached the lowest when N application rate was 495 kg/hm². Quadratic polynomial model showed that the maximum yield of N application rate and economic optimum nitrogen application rate were 341.7 kg/hm² and 327.1 kg/hm², respectively, and showed no significant difference. Therefore, under the condition of the experiment, the suitable application rate of nitrogen fertilizer for winter potato should be controlled within 270-327.1 kg/hm² for the higher yield and economic benefit.