The invention provides a pipeline compressor model stage with the flow coefficient being 0.0354. The pipeline compressor model stage comprises an impeller, a vaneless diffuser, a curve and a backflow device. The impeller is located at the inlet position of the model stage. The vaneless diffuser is arranged at an outlet of the impeller. The backflow device is located at the outlet position of the model stage. The vaneless diffuser communicates with the backflow device through the curve. According to the model stage, the machine mach numbers M are equal to 0.35-0.65, the design point flow coefficient phi<1> is equal to 0.0354, the design point energy head coefficient tau is equal to 0.605, the polytropic efficiency eta under the design flow coefficient working condition of the mach numbers is equal to 0.849-0.854, and the application flow range is 60%-150% of that of a design point. The invention further provides a design method of the impeller of the model stage. The model stage is high in efficiency and energy head coefficient, large in hub ratio and small in span; and through the adoption of the model stage, a light medium compressor can have the high operating efficiency and the wide working condition range, meanwhile, the working rotating speed of a rotor can be decreased, the bearing span can be reduced, and the stability of the rotor can be improved.