Abstract: This paper aims at optimizing the cure cycle of specific encapsulation structures composed of E51 resin from room temperature cure cycle to medium-high “two-phase” cure cycle by means of combination of numerical simulation and experimental testing on the basis of experimentally obtained parameters of cure kinetics and mechanical properties for E51 epoxy resin. The numerical method was firstly adopted to simulate the effects of temperature magnitude and curing time in the first and second dwelling phase to internal temperature, degree of cure and strain of structure during curing to optimize the process parameter. Then the internal temperature and strain of the structure were real-time recorded using Fiber Bragg Grating (FBG) monitoring technique, and the corresponding results reveal the validity of numerical simulation, which demonstrates the reliability of the approach of optimizing the cure cycle using numerical simulation. Lastly, the properties of the casting body specimens of E51 resin manufactured with optimized and original cure cycle were compared, and the results show that the tensile strength, compressive yield strength, flexural strength and impact strength for the specimens manufactured with optimized cure cycle increase by 3.9%, 1.5%, 14.5% and 16.2% compared with the specimens manufactured with original cure cycle, respectively.