The article researches and analyses the temperature of two kinds of new hot knife. And it also does the thermal analysis by Pro/e MECHANICAL about the special steel hot knife. It shows the integral and steady-state distribution of the temperature of the metal knife and proves the accuracy of the experimental data. Through the practical production, the ideal result of the cutting surface can be obtained by controlling the temperature. The article also makes the contrast of the two kinds of surfaces by the electron microscopy. By the contrast, the surface which meets the technological requirements can be obtained by the cutting of the hot knife.