Abstract: The strength characteristics of materials composed of polymer curing agent(PCA)-basalt fiber(BF)/sand composite were deeply studied by uniaxial compression test, direct shear test and direct tensile test, the effects of polymer curing agent content, basalt fiber content (mass ratio to dry sand) and sand density on the strength of the composites were compared and analyzed. And the strength enhancement mechanism of PCA-BF/Sand was analyzed based on the results of the tests and SEM images. The test results show that:The compressive strength, shear strength and tensile strength of PCA-BF/Sand are obviously enhanced after mixed with basalt fiber and polymer curing agent, and the residual compressive strength increases with the increase of content of polymer curing agent. With the increase of the content of basalt fiber and the polymer curing agent, the strength of PCA-BF/Sand increases rapidly first, and when the polymer curing agent content and the fiber content reach 3% and 0.6%, the increase is slowed down. With the increase of PCA-BF/Sand density, the compressive strength and shear strength of the composites have been increased, and the tensile strength decreases first and then increases and then decreases and reaches maximum at a density of 1.55 g/cm³. With evaporation of water, polymer curing agent formed space network between sand particles, therefore, scattered sand were connected with each other to become an integral whole, and the basalt fiber added into sand can play a reinforcing role in the sand, thereby the strength of PCA-BF/Sand composite was effectively improved.