Abstract: Landslides are usually reinforced by anti-slide piles, and a very important problem is to determine the reasonable position of the anti-slide piles in the slope. It is considered that the optional position of the anti-slide piles is the position which can make the largest safety factor of the landslides. Based on the deformation field obtained by variable modulus of strength reduction method, this study finds that when the anti-slide piles setting in the position which has the largest displacement of the landslides can get the maximum safety factor, therefore, a reasonable location of the reinforcement by means of the anti-slide piles can be determined through the deformation field. The proposed method is convenient and reasonable. The results obtained can be a reference value to determine the location of the anti-slide piles.