Metal solid transformation is simply classified into shear and diffusion type, which would lead to doubt and e-ven confusion. According to Christians suggestions, the phase transformation of chemical composition invariant, such as polymorphous transformation, massive transformation, grain growth and recrystallization, should be separated from the diffusion type of phase transformation, and into that of rate - controlled by processes. The microscopic distribution asymmetry of the elements in steels such as Si, Cr and etc. , have certain effects on the formation of carbon - depleted zone during isothermal transformation of the supercooled austenite in the incubation period, and such effects should be considered together with the effects of crystal defect. The thermodynamics analysis sketch map ( parent phase and product phase composition -free energy curve) is deduced from the fundamental laws of thermodynamics, should not be taken to explain the original regulation and taken as the primary argument to analyze the problems, and append much confused trivialness.