The axial force of concrete support is abnormally increased in the half cover excavation deep foundation pit project of Wuhan road station of Luoyang Metro Line 1. The values are far larger than the design control values. So the factors causing the increase of the axial force of concrete support are discussed by using the method of numerical simulation. The results show that the load beside pit, the position of the steel support close to the concrete support and the axial force all have a significant impact on the axial force of the concrete support. The main factor causing the increase of the axial force of the foundation pit concrete is the large load generated by the construction machinery and vehicles on the open cut side. Therefore, the load value of foundation pit should be controlled in the project, and the steel support should be erected in time and the axial force of steel support should be supplemented in time during the excavation process.