In order to ensure national energy security, The well site adopts gas displacement technology to improve the oil recovery rate, The gas content of the produced liquid caused by gas displacement technology increases, and the high gas content crude oil has a great impact on pumping efficiency and production safety, hydrocyclone separators (tangential inlet) are often used for gas-liquid separation, although its separation efficiency is relatively high, however, there are issues such as complex structure and inconvenient installation, furthermore, the processing capacity is strictly limited by the size of the oil well casing. In response to the above issues, we propose using axial liquid injection, 1.5° internal cone, 30° overflow mouth structure cyclone for gas-liquid separation, And gas-liquid separation numerical simulation test for four cases of volume gas content: 0.01, 0.1, 0.2 and 0.3. The results show, The separation efficiency is highest at the gas content of 0.1, Reach more than 95%, The gas-liquid separation effect is better when the gas content is 0.2 and 0.3, which can reach more than 85%, The worst separation was achieved at a gas content of 0.01.