Abstract: Based on the similarity between adiabatic shear instability and fluid boundary layer, the governing equations of adiabatic shear instability are established by the generalized boundary layer theory. The governing equations are dimensionless by the method of dimensional analysis, and the generalized Reynolds number which can represent the inertial effect is obtained. At the same time, the dimensionless governing equations are solved by the method of linear perturbation. The influence of inertia effect on adiabatic shear instability is analyzed. The results showed that the adiabatic shear instability would be restrained when the inertia effect reaches a certain critical value, and the restraining effect would increase with the increase of inertia effect.