Abstract: A series of model tests are carried out to investigate the pull-out behavior of a suction caisson foundation in sand, and the effort is focused on the effect of aspect ratio, loading inclination angle and load attachment point. Three different aspect ratios, five different loading inclination angles and five different load attachment points are considered in the model tests. The test results show that the characteristics of load-displacement of the suction caisson foundation before pull-out are different in each case. The pull-out capacity can be improved significantly by increasing the aspect ratio. However, changing the aspect ratio does not affect the deformation characteristics of the suction caisson. The more nearly horizontal the loading direction, the greater the pull-out capacity of the suction caisson foundation. The influence of the loading position on the pull-out capacity of the suction caisson foundation can be ignored while the loading inclination angle equals 90000b0;, otherwise the load should be attached on the suction caisson height of 2/3 and 3/4 to obtain greater pull-out capacity.