In order to compensate the shrinkage of inorganic polymer pastes uniformly and quickly,reactive MgO powders were evenly dispersed in the inorganic polymer pastes,and the deformation,mechanical property,microstructure and component of the inorganic polymer pastes doped with the reactive MgO were investigated.The results indicate that,when the dosage of the reactive MgO is 6%,the chemical shrinkage,autogenous shrinkage and drying shrinkage of the inorganic polymer pastes decrease respectively by 10. 7% at 28d,72. 1% at 7d and 20. 0% at 28 d,which means that the shrinkage of the inorganic polymer pastes in a hardening process is effectively compensated by the reactive MgO,In addition,after the reaction of the reactive MgO with the water in a high-alkalinity liquid-phase environment,fine wormlike Mg( OH) ₂ crystal forms and causes a uniform expansion in the inorganic polymer pastes,which refines the pore size of the inorganic polymer pastes and enhances their compressive strength,so that the compensation of the reactive MgO for the shrinkage of the inorganic polymer pastes is accomplished.