Electric aircraft provides a bright technical way to achieve completely green aviation. The electric propulsion system is the power and energy source of electric aircraft. Therefore, a parameter matching of the electric propulsion system plays a key role on the environmental protection, energy-reservation and high efficiency of electric aircraft. First, a brief overview of the electric propulsion system is completed, and the characteristics of its components are analyzed. Secondly, combining the characteristics of the electric propulsion system of the current electric light aircrafts, the design process of type selection and parameter matching of the propulsion system is discussed. Then, according to the characteristics of components of the electric propulsion system, a method of type selection and parameter matching of electric light aircraft propulsion system is put forward, including type selection and parameter matching of the propeller, type selection and parameter matching of the motor, type selection and parameter matching of the controller, type selection and parameter matching of the battery pack. The method can provide the basis for optimization design of the electric propulsion system. Finally, the method is verified with the RX1E electric light aircraft, and the matching results meet the design requirements, which illustrates the feasibility of the method.