Abstract: Through the tensile tests, the tensile properties of fiber reinforced polymer (FRP) sheet exposed to severe environment were studied. Test parameters included the category and working way of severe environment, the type and layer of FRP sheet. The experimental results show that the tensile stress-strain curves of carbon fiber reinforced polymer (CFRP) sheet and glass fiber reinforced polymer (GFRP) sheet are approximately straight line at ambient temperature and after the action of freeze-thaw cycles and dry-wet cycles, the tensile strength and elongation of CFRP sheet and GFRP sheet at ambient temperature are almost not affected by the number of sheet. The effect of freeze-thaw cycles on GFRP sheet is larger than that on CFRP sheet; the tensile strength of CFRP sheet and GFRP sheet after 75 cycles of freeze-thaw is 0.978 and 0.898 times as much as 0 cycle of freeze-thaw respectively, and with the increasing number of cycles, the tensile strengths of CFRP sheet and GFRP sheet are gradually decreased; wet and dry cycles have no obvious effect on GFRP sheet. Based on the analysis of test results in the literatures and this paper, the calculation method of tensile strength of FRP sheet exposed to severe environment has been presented.