Abstract. For the slow process of hydration and complex process of hydration of cement-based composite biomass materials, the paper study the compatibility of straw cement mixed system was evaluated in process of hydration. By testing temperature changes in process of hydration of cement-based composite biomass materials and analyzing the maximum value of hydration temperature, the maximum temperature difference and compatibility coefficient of modified the cement-based composite biomass materials by agent, taken before or after that. It was evaluated that compatibility performance of modified the cement-based composite biomass materials by agent. The results show that the characteristic changes of early hydration heat was reflected with a visual aid by some indexes that are the maximum value of hydration temperature, the maximum temperature difference, and so on. And the early hydration behavior was more comprehensive objective reflected by compatibility coefficient in cement-based composite biomass materials. At the same time, the modified effect of sodium silicate was superior to the polyvinyl acetate (PVAc) in the early hydration of the cement-based composite biomass materials.