Frictional force produced by the accumulated wax plug plays a dominant role in pipeline pigging. In order to calculate the frictional force, frictional behavior of wax-oil gels was investigated using a home-made tribometer. Effects of several impact factors, including wax concentration, normal force, and sliding velocity, on tribological behaviors of the wax plug were discussed in this study. The results show that the maximum static friction and the coefficient of sliding friction are negatively related to wax concentration. Sliding friction force was found to increase with normal force. Coefficient of sliding friction increases with velocity at the concentration of 20wt% wax. A physical model describing the contact of two wax-oil gel surfaces was built based on the experimental results.