The mechanical property and the durability of SD622S polymer modified concrete were studied. The economics of the material was analysed. The increase of the flexural strength, the decrease of the compressive strength and modulus, the increase of flexural fracture energy, the improvement of fracture properties, the improvement of the durability and performance price of SD622S polymer modified concrete were showed. The mechanism of the property improvement of the material was discussed from the aspect of micro structure analysis. The results verify that SD622S polymer interlocks into the film network in concrete, increases the specific surface of cement and intensifies the cement hydration. Therefore, the strength of concrete increases and durability is improved.