To obtain better performance on unstructured environments, such as in agriculture, forestry, and high-altitude operations, more and more researchers and engineers incline to study classes of biologically inspired robots. Since the natural inchworm can move well in various types of terrain, inchworm-like robots can exhibit excellent mobility. This paper describes a novel inchworm-type robot with simple structure developed for the application for climbing on trees or poles with a certain range of diameters. Modularization is adopted in the robot configuration. The robot is a serial mechanism connected by four joint modules and two grippers located at the front and rear end, respectively. Each joint is driven by servos, and each gripper is controlled by a linear motor. The simplified mechanism model is established, and then is used for its kinematic analysis based on screw theory. The dynamics of the robot are also analyzed by using Lagrange equations. The simulation of the robot gait imitating the locomotion of real inchworm is finally presented.