In order to develop the bonding and sealing materials for high integrity container with large flowability, high strength and high durability, so as to meet the requirements of 300 years service in a variety of harsh environments during the process of low and intermediate radioactive waste disposal, ordinary Portland cement and silica fume were used as cementitious materials, and fine quartz was used as intert filer. Based on the most compact stacking theory, preliminary formulation was obtained. Micro silica powder was introduced to partially replace cement, and rheological properties, pore structure, mechanical properties and durability of sealing materials were investigated. The results show that micro silica powder improves the fluidity and rheological properties, reduces the porosity at 28 and 56 d, and improves the splitting tensile strength, shrinkage resistance, chemical attack resistance, seepage resistance and freeze-thaw resistance of sealing materials, but the effect of micro silica powder on compressive strength and static elastic modulus is not obvious. After adding 10% (mass fraction) micro silica powder into cement, the properties of sealing materials are higher than those required by the Chinese standards and satisfies the demand of 300 years of service in harsh environment.