Abstract: The effect of four factors. i. e. vanadium content in steel,deformation temperature,deformation rate,cooling rate,on high temperature thermoplasticity of low alloy vanadium steel was quantitatively investigated on GLEEBLE-1500 thermal-mechanical simulator by means of orthogonal design test. A mathmatical models describing the relation between four factors and thermoplasticity of steel have been developed by the use of mathmatical regression method,which will provide an important basis for making reasonable vanadium steel continuous casting technology.