The six-bar tensegrity is balanced by the internal force distribution between the cable and the bar,and has the characteristics of large displacement and strong nonlinearity,which has large application potential in the robot field of planetary exploration.To obtain the nonlinear mechanical properties of the structure,the mathematical analysis model of the six-bar tensegrity was constructed by the node matrices,adjacency matrices,and vector matrices.On this basis,considering the geometric nonlinearity of the structure,the mechanical analysis model was established,and the influence of different loads and structural parameters on the mechanical properties was analyzed.The deformation sensitivity of each parameter was calculated,and the effective method to improve the stiffness of the six-bar tensegrity was obtained.Finally,the six-bar tensegrity robot prototype was fabricated and the rolling over experiments were implemented.This conclusion can provide certain theoretical support for the follow-up structural optimization and kinematic control.