During the curing process of composite in autoclave, the curing deformation of the workpiece is still an important factor affecting the quality of forming. By using fiber Bragg grating and thermocouple sensors, the temperature and strain of composite part are monitored on line during the autoclave curing process. The influence law of resin matrix on strain in part is studied, and based on this, the influence of different mould materials on strain in composite curing process is analyzed. Experimental results show that resin and mould are the main influence factors of strain variation in composite materials curing process: On temperature rising and holding stage, the strain variation is caused by the resin flow, thermal expansion and curing reaction, while the mould contraction will contribute most to the strain variation on the cooling stage. The change of stiffness, binding capacity with parts and thermal expansion coefficients of different mould materials will affect the strain variation in different stages of composite curing process. The curing strain curves of composite material parts under the curing process with different material moulds are obtained, the influence of different mould materials on strain in composite curing process is analyzed, and the conclusions have instruction significance to large composite parts curing deformation for further analysis.