The socketed depth in rock-socketed pile can influence its bearing mechanism largely. At present the numerical simulation is used to study the socketed depth’s influence on pile’s bearing mechanism. It can reveal the pile bearing mechanism in some degree; however, there are some defects and limitations in simulation for its assumptions and simplifications. Based on the pile foundation of Tian-xing-zhou Bridge, the model test is conducted to study the socketed depth’ influence on rock-socketed pile bearing mechanism. In the model test, the socketed depth of model piles are made different ranging from 60mm to 200mm at the step of 20mm, and the bed rock is simulated with mixture of sand and plaster, the rock-soil overlain the bed rock is simulated with silty sand, the pile is simulated with organic glass rod according to similarity principle respectively. The results show that the settlement of top of model pile is smaller and the ratio of point resistance is smaller when the socketed depth is longer. When the socketed depth reaches 5D (D represents diameter of model pile), the ratio of point resistance is no more than 40%, and it is less than 1% when 8D. The conclusions drawed from model test are useful to deciding the length of pile foundation in Tian-xing-zhou Bridge.