The operational track forecast of Typhoon Muifa (2212) is quite difficult due to the complex circulation, the large dispersion of the ensemble forecast and multiple adjustments of numerical models at different initial times. Based on the CMA-REPS (China Meteorological Administration-Regional Ensemble Prediction System), this paper compares the environmental flow fields and circulation characteristics of the members with small mean track forecast errors verified against the best track (the easterly group) and the members with large mean track errors (the westerly group). It is found that the easterly group corresponds to a southerly subtropical high, which is prone to merging with the high pressure in the southern part. The southerly steering flow is more conducive to the northward and eastward movement of the typhoon. The pattern and position of the subtropical high are also the main reason for the adjustment of the ensemble forecast at different initial times. In addition, the easterly group has larger typhoon size than the westerly group, and the typhoon and its surrounding circulations also contribute to the northward motion as a result of the β-effect propagation. The land vortex has much more complex impact on the typhoon track. The development of the vortex close to the typhoon is beneficial for the westward movement of Muifa and has an “attractive”effect on the typhoon, while the development of the vortex far away from the typhoon is not conducive to the westward movement of the typhoon and has little impact on the track. The contribution of typhoon size and cut-off vortex to the track forecast is relatively small compared with the subtropical high. In operational forecasts, it is important not to overestimate the attraction of high-level troughs or vortices to the typhoon track.