Typhoon Talim is very similar to “Saomai,” but the influence that it caused differs greatly after typhoons landed. In combination with the objective analysis, conventional observation, surface radiosonde, mesoscale automatic weather station and numerical simulation data, the formation mechanisms of the differences in precipitation and wind fields of the two typhoons are studied. When Talim landed and moved northward, along with the westerly trough, a stabilized synoptic pattern, in which there was a deep tough in the middle troposphere in the north and a southwest vortex in the lower troposphere in the south, came into being, with weak cold air infiltrating southward in the boundary layer. When Saomai landed and moved northward, there was a highpressure “dam” in north without cold air activity. For Talim, the highenergy area was situated in the north of Zhejiang, and there was mesofrontogenesis and weak instability. For Saomai, the lowenergy area was in the north of Zhejiang, and the atmosphere was quite stable. It is concluded that similar typhoons may produce greatly different influences.