To deal with the environmental characteristics of transmission lines and the demands for their maintenance, a novel inspection robot mechanism is presented. The mechanical model of driving wheel traction is analyzed and the quasi static mechanics model of two-wheel driven robot is set up. Through the optimization of driving wheel structure and the adjustment of the robot rolling posture, the robot's climbing ability is improved along with enhancing the adhesion for ascension. The different structures of wheel configuration and different postures before and after the optimization planning are simulated. The prototype is developed and the experiment of the robot climbing ability is tested in the lab. The simulation and experimental results show that the mobile robot ability is improved by optimizing its attitude and changing the wheel structure.