Vehicles and agricultural machinery are often trapped caused by slipping and sinkage when working on soft terrain. Therefore, a superior propulsive performance is significant for the vehicle. By observation of the dactylopodites of Chinese mitten crab, three bionic soil contact parts with different cone angles were fabricated. The article focused on the drag force in the horizontal movement of soil contact parts, which were compared with cylinder sample. Experiments of walking foot were carried out in soilbin filled with fine quartz sand. The influence of motion velocity, insertion depth and cone angle to the drag force were analyzed. Results showed the drag force was increased with the square of insertion depth and the cone angle of soil contact part. When the cone angle of bionic walking foot was doubled and trebled, the drag forces were increased by 47.18% to 167.57%. And the drag force was linearly correlated with motion velocity. In the scope of velocity of experiments, the drag force was increased by 11.37% at most with the increasing velocity. A model for predicting the drag force of walking foot was created based on the estimating formula proposed by ALBERT, and was combined with the experimental results. The verification of the model showed that the residual was not higher than 3.62N and the average relative error between the model calculation values and experimental data was lower than 22.77%. Thus the model can be used for both variable section and equal section soil contract part, and it was accurate enough in the prediction of the drag force. The research results provided theoretical basis for predicting the performance of propulsion of the soil contact part and the development of legged mechanisms on soft terrain.