Abstract: Based on CONVERGE software, a numerical simulation model for gasoline Wankel rotary engine was established and validated by the experimental data. The investigation was conducted under the side-ported, peripheral-ported, and combination-ported structure, respectively. Then, the influence of different inlet-ported structures on the combustion process of the engine was studied comparatively, such as the flow field, flame propagation, and emissions formation. Results show that different inlet-ported structures lead to the pronounced difference in the flow field. Compared with the side-ported and combination-ported engines, the mixture velocity of the peripheral-ported engine near the top dead center increases by 16.41% and 6.57%, respectively. The peripheral-ported engine exhibits the fastest flame speed and the highest combustion velocity in all cases. The peak in-cylinder pressure of the combination-ported engine is 6.05% higher than that of the side-ported engine, and its corresponding crank angle is advanced by 4.95°. When the combustion chamber connected to the exhaust port, the nitric oxide formations of the side-ported engine is the lowest, and the carbon monoxide of the combination-ported decreases by 1.03%, in contrast to the side-ported engine.