Abstract: This paper presents an experimental study on the axial compressive behavior of 54 rectangular prisms confined with basalt fiber-reinforced polymer (BFRP). The influences of the BFRP layers, corner radius and aspect ratio on the tensile strain reduction factors of BFRP were investigated. The test results show that the tensile strain reduction factors calculated based on tensile strains in sides and average tensile strain of lateral BFRP sheets will overestimate confinement efficiency. Based on tensile strains at the corners, a computing method of tensile strain reduction factors of BFRP sheets was proposed. According to the proposed computing method of tensile strain reduction factors and experimental data in this paper, the hydrostatic pressure balance equation of the cylindrical BFRP membrane was used to build an axial ultimate compressive stress model of BFRP-confined rectangular concrete. Based on a large collection of test data, predicted results of the proposed model and the existing typical models were compared and analyzed. The rationality of the existing typical models was verified. The prediction accuracy of the proposed axial ultimate compressive stress model is higher than the existing typical models.