The paper emphasizes the superiority of pressure anchor cable, and analyzes the necessity of combining soil anchor and anchor cable for soft soil deep foundation pit. After thinking about the past design, it is suggested that the safety factor of slope and foundation pit engineering should adopt three stages: k up, k middle and k down, where k down > A surname On k, the average value of the three meets the standard k value. It is also pointed out that under certain conditions, the overall stability of the anchor cable should be considered in the design. The temperature stress of bolt in rock slope in tropical area cannot be ignored.