In 2016 and 2017, two drip irrigation frequencies (the low frequency W1:one irrigation every 7 days, the high frequency W2:one irrigation every 2 days) and two nitrogen levels (suitable N1:375 kg/hm², high nitrogen N2:565 kg/hm²) were conducted in a solar greenhouse of squash in the northern cold and dry land, with the same irrigation quota of 269.87mm. The soil water and nitrate distributions and the yield of squash in solar greenhouse were studied. The results showed that:(1) W2 increased the soil water contents of 0-40 cm and reduced the deep seepage. (2) The soil nitrate contents were higher in all layers under N2, suitable nitrogen treatment combined with high frequency drip irrigation could maintain the nitrate contents at a relatively suitable level at 0-40 cm in the root zone, so the nitrate content in the 40-80 cm soil layer was relatively lower. The improved frequency of drip irrigation could reduce the leaching risk of nitrogen. (3) Under N1, squash yield was sensitive to irrigation frequency, however, for N2, the increasing irrigation frequency had no significant effect on yield, which indicated that the sensitivity of squash yield to irrigation frequency was low. (4) For a given fixed irrigation quota, the effect of drip irrigation frequency on water use efficiency of squash was greater than that of nitrogen fertilizer on water use efficiency of squash. (5) Taken together, W2N1 was more conducive to the growth of squash and the increase of yield. So, it is recommended that the nitrogen level in greenhouse drip irrigation was 375 kg/hm², and the irrigation frequency was 2 days.