Abstract: Compared with pile foundation,suction caisson has the advantages of convenient construction and recyclability,and is more suitable for deep sea area. Horizontal cyclic response is important for the stability analysis of suction caisson as it suffers the long-term wave loads in service period. This paper presents the results of a series of 1g model tests under horizontal cyclic loading in sand. The cumulative deformation,rotation angle and rotation center of model caisson are discussed in detail. Test results indicates that the horizontal displacement of model caisson in sand accumulates with increase of cyclic numbers and horizontal loading. Under the horizontal cyclic loads of ζ_b=0.33 and 1.0,the change rule of bucket caisson rotation angle and rotation center is consistent with the cumulative deformation. After 50 cycles,the cumulative rotation angle is 1.43 times and 1.76 times of the first cycle under different cyclic load ratios. With the increase of the number of cycles,the position of the rotation center gradually moves upward,and finally stabilized at about 0.8L below the sand surface. This study can provide theoretical basis for the design of suction caisson as offshore wind power foundation in sand.