ABSTRACT This paper mainly introduces the design of the 387 diesel engine parts of piston group. In this design, considering the 387 diesel engines are mainly applied in small and medium-sized machinery, agricultural production environment is bad, need often has better performance for internal machinery products provide enough power. The Diesel 387 which designed this time is on the basis of the old Diesel 387 and increasing the piston stroke, with its power performance and economical efficiency enhanced. However, because of the work itinerary increased, its balance became worse, noise and vibration also increased. So in this design, I have to take some certain measures. Combustion Chamber using injection type, easy to start, energy saving effect, and can make the efficiency and performance improved greatly. The engine speed is 3000r/min, about 27kW/12h calibration power, speed and the current low power of the car needs. Through the parameters and process performance control can make fuel consumption in 245g/kW. This paper discusses the design requirements and characteristics of the cylinder important parts。 My main task is to design 387 engine parts of piston group. On the first, according to the diesel’s performance target, I should to choose the main performance mark of the diesel. Then in the light of the design of 387 diesel parts of piston group to design the structure. When explained the process of the parts of piston group design, I also summarized the main parts. This thesis focused on expounding the foundation and process of the 387 diesel engine parts of piston group design. KEY WORDS: diesel engine, the piston, the connecting rod,