Abstract: The microstructure characteristics of Ti-46.5Al-2.5V-1.0Cr-0.3Ni alloy were studied by high temperature compression tests at temperatures from 1 000 ℃ to 1 200 ℃,strain rates from 0.001 s-1 to 1.0 s-1 and strains from 0% to 70%.The influences of test parameters on the deformed microstructure were analyzed.Based on the tests,BP artificial neural network model of the microstructure evolution of the alloy during high temperature deformation was established,and the accuracy of the predicted results was tested.The results show that during high temperature deformation with the increase of strain and temperature and the decrease of strain rate,the equiaxed grains formed throngh dynamic recrystallizalion increased and the residual lamellar colony decreased.The model for deformation microstructure at elevated temperatures could accurately predict the microstructure changs of the alloy during the deformation at elevated temperatures.The average error between predicted values and measured values was 2.82% for the volume fraction,and 0.22 μm for the grain size of dynamic recrystallization.