Based on a series of geological and geochemical evidence, the paper expounded, in detail, the natural gas migration and accumulation of the Yinnan 2 gas pool in the Yingjisu Sag, northeastern area of the Tarim Basin. It was represented that the natural gas in the Yingnan 2 gas pool came mainly from the Cambrian source rocks, which was a cracking gas from oil in the Cambrian accumulated in earlier period. The gas pool-forming period might be mainly in the terminal of Yanshanian orogeny, with a gas migration channel being fractures which connected the ancient oil pool in the Cambrian and the overlying Jurassic traps. It was the accumulation process of the Yingnan 2 gas pool that resulted in the defference from the oil-gas accumulations in the neighboring structures, also, the features of natural gas geochemistry of the Yingnan 2 gas pool were different from that of the neighboring gas pools. Based on mentioned-above, the exploration direction in northeast Tarim in the near future was discussed.