The utility model relates to a temporary stair erected by scaffolds in order to solve the existing problems. The temporary stair erected by the scaffolds is simple, easy to implement, safe and reliable, solves the problem that workers cannot get on or get off the working surfaces safely, and enriches a project safety management system. According to the technical scheme, the temporary stair erected by the scaffolds is provided with the scaffolds erected in the building process of a building, and is characterized in that the temporary stair used for communicating the upper working surface and the lower working surface of the building is erected between the three rows of vertically parallel existing scaffolds beside the building, the temporary stair comprises upwards inclined floors and a horizontal transition floor, the upwards inclined floors are arranged between every two adjacent rows of scaffolds, the top end of the inclined floor on one side of the middle row of scaffolds is connected with the bottom end of the reversely upward inclined floor on the other side through the horizontal transition floor, and temporary stairs are erected and connected in a cyclically upward mode sequentially until to the reserved elevation. The temporary stair erected by the scaffolds is applicable to the field of buildings.