Abstract: Fixed tensile, tensile and shear tests were carried out on styrene-acrylic emulsion-based cement composite specimens with six different cement-powder ratios to measure the elastic recovery rate, tensile and shear mechanical performance indicators, deformation performance indicators, energy consumption performance indicators and load displacement of the specimens, thereby the effects of cement-powder ratio on the fixed tensile bonding performance, tensile mechanical properties, shear mechanical properties and failure forms of the specimens were studied. And the microscopic mechanism of cement-powder ratio influencing on the mechanical properties and failure forms of the composite was analyzed based on the results of FE-SEM test and Mercury Intrusion Porosimeter(MIP) test. The results show that increasing the cement-powder ratio appropriately can improve the microstructure and optimize the pore structure of the composite. In addition, it can also improve the compactness and significantly enhance the mechanical properties of the composite. With the increase of the cement-powder ratio, the fixed tensile and bonding performance of the specimens gradually decreases, the tensile and shear mechanical performance are continuously improved, and the tensile and shear deformation performance and energy consumption performance of the specimens firstly increase and then decrease. When the cement-powder ratio is between 30% and 35%, the tensile and shear mechanical properties of the specimens are the best. When the cement-powder ratio is 45%, the tensile and shear deformation performance and energy consumption performance of the specimens are worse than the specimens with the cement-powder ratio of 20%. As the cement-powder ratio increases, the load displacement that the specimens can withstand gradually increases firstly and decreases, and the failure form of the specimens gradually changes from “cohesive failure” to “bond failure”.