Abstract: Dish solar thermal power generation system is characterized by such features as high conversion efficiency, thermal energy storage capacity and good economic performance. However, the large-scale application of existing dish solar thermal generation power systems is limited by its bulky concentrators, complex thermoelectric conversion device structures, low power-to-mass ratios, and high construction costs. A portable concentrating solar thermal-mechanical-electrical conversion device (CST-M-ECD) is designed in this paper. Firstly, according to the system heat input and expected indicators, the device collector temperature, circulation thermal efficiency and output power are calculated. Then, the appropriate component program is selected and the structure and parameters are designed in detail according to the requirements. Finally, kinematics simulation analysis of the scroll expander (the device's core output component) is carried out for verifying the correctness of its modeling and motion characteristics. The device features a cleverly compact structure, small size, light weight, and rational component layout, which enables the dish solar thermal power generation system to achieve lightweight design and easy portability.