The effects of three heat treatment regimes and two cooling ways on the microstructure and tensile properties of IMI834 titanium alloy were studied. An optical microscope was used to analyze the evolution of the microstructure of the alloys in different heat treatment states; Image-Pro Plus v5.1 (IPP) and Nano Measuer image analysis software were used to calculate the size of equiaxed α phase (α_p) and secondary α(α_s) clusters in the microstructure; The crystal orientation and the deformation behavior of the alloy in situ before and after deformation were characterized using in-situ SEM tensile test and EBSD technology. The fracture morphology of the material in the different cooling speeds was analyzed using scanning electron microscope.The distribution of second phase was analyzed by TEM. The results show that:in the double annealed test,with the increase of the first annealed temperature,the content and the size of α_pgradually decreased,but the secondary α clusters increased.With the increase of the first annealed temperature, the strength of IMI834 alloy first increased and then decreased. The elongation and reduction of area did not change significantly.When the first annealed temperature is 1020℃, the strength of IMI834 titanium alloy reaches the highest under the two test conditions of sample heat treatment (rapid cooling) and block heat treatment (slow cooling).The strength of the sample heat treatment (rapid cooling) is higher than that of the block heat treatment (slow cooling) by about 50 MPa; In the early deformation stage of IMI834 alloy, the crystal rotation angle of fast cooling is generally higher than that of slow cooling;The existence of the β phase between the α_pand α_s can ensure that the slip transfer can still be carried out under low geometric compatibility factor; The quasi-cleavage facets of the fracture surface under fast cooling conditions is ellipsoidal or polygonal, and under slow cooling conditions, it is elongated. The difference of the distribution of second phase in the α/β bounderies is the reason for the different morphologies.