The influence of gas injection cycle，production pressure and permeability on the huff and puff effect of tight oil reservoir in the Lucaogou Formation of Jimsar Sag of Junggar Basin were analyzed through the physical simulation experiment of N2 huff and puff of the cores. The results show that cycle recovery rate decreases and the huff and puff effect becomes worse with the increase of huff and puff cycle；after 5 cycles，the cumulative recovery rate is increased by 6.81%-13.88%，which was about 2.5-3 times of that of elastic depletion，but the oil recovery is increased mainly in the first three cycles. Low production pressure and high permeability can bring larger cycle recovery rate and higher utilization of injected gas，and thus the effect of huff and puff is better. According to the experiment results，it is considered that there is feasibili? ty of N2 huff and puff in the study area. When the reservoir permeability is low，it is necessary to take measures such as fracturing and acidification to improve the reservoir permeability and the huff and puff effect，but the huff and puff should not exceed three cycles.