Abstract: Effects of hot rolling reduction on the microstructure and hydrogen embrittlement of 430 ferrite stainless steel in biphasic region (1000℃) were studied.The results show that the ferrite stainless steel microstructure after hot rolling in biphasic zone is deformation martensite and ferrite; with the increase of deformation, the plasticity of the material decreases gradually, the yield strength and tensile strength increase obviously, and the hydrogen embrittlement sensitivity increases gradually.After hydrogen filling, the samples shows serious plastic loss and obvious decrease in strength, and the fracture surface changes from cleavage+a small number of dimple morphology to complete cleavage brittle fracture morphology.