Abstract: In view of the structural deformation, weight and high-temperature requirements in the application of titanium engine compartment rear structure of a certain aircraft, composite structural design was carried out instead of titanium alloy for aircraft engine compartment rear structure, taking the AC729RTM polyimide composite with temperature resistance of 350℃ as design material. The finite element (FE) model of composite engine compartment rear structure was generated to perform parameter analysis and reasonable structural design parameters were obtained. The composite engine compartment rear structure was fabricated by resin transfer molding process (RTM). Finally, verification and evaluation were carried out from static strength test, structural deformation and weight. The results show that the internal quality and appearance of polyimide composite engine compartment rear structure are in good condition except for pores of small areas (porosity<2%) through non-destructive inspection. There are no obvious damages in engine compartment rear structure except for debonding of small areas through verification of static strength test, and satisfied the requirement of room temperament strength. The shape deviation of composite engine compartment rear structure is controlled in –0.808-0.664 mm and is better than titanium alloy structural. Compared with titanium alloy structural, the mass is reduced by 27.5%, achieving good benefits.