Abstract: In this paper, the engineering geological conditions of one construction site in Beijing has been described in details based on the field investigations. As to the 6 typical slopes, stereographic projection method and limit equilibrium method have been used to analyzed the stability of them. For limit equilibrium method, complex plane sliding and three dimensional wedge analysis model were adopted. The analysis results show that the engineering geological conditions of the site is relatively simple, the rock mass is main of layered structure. The stability of the 6 slopes in the site is relatively well. However, there is a fault cut through the site, therefore, the stability of slope No.2 should be paid more attention to. Combining the slope stability and high availability of building sites, the protection method of slope excavation, retaining wall and slope surface protection were proposed.