The alignment installation work of Hefei Advanced Light Facility (HALF) is usually carried out in tunnels. Calculate the key component points to the global coor-dinate system through coordinate conversion, and accu-rately adjust them to the corresponding coordinate values for alignment and installation. However, long and narrow tunnels can easily cause dense common points, resulting in a loss of accuracy. Therefore, to quickly and accurately obtain the coordinate transformation parameters, this article proposes a common point selection method with uniformity normalization and selects the optimal com-mon points set based on the normalized uniformity in different directions. The feasibility of this method was verified based on experimental data. The results show that the conversion parameters solved by this method are more accurate, avoiding accuracy loss due to aggregation in a certain direction, and are suitable for long and narrow tunnels.