Taking low heat cement cementitious system as research object, the effect of types and content of mineral admixture on its compressive strength and hydration heat was studied. A prediction model of mechanical and thermal properties of low heat cement cementitious system based on projection pursuit regression(PPR) was proposed, accuracy discrimination criterion was summarized, and the sample selection criteria of PPR was established. Through simulation calculation and comprehensive performance contour map, comprehensive performance optimization of cementitious material system could be transformed into the optimization of its mechanical and thermal single target properties. The comprehensive performance optimization method based on PPR model could directly determine the mechanical and thermal index and their mix proportion without subjective weighting and assumed modeling, which provides guidance for the application of low heat cement cementitious system in large volume concrete.