The entry and exit side pinch roll unit of the reversing finishing mill of stainless hot strip rolling mill line bears heat effects during producing. Its transfer convection must be sufficient to maintain its function. According to the original pinch roll unit during producing, there are four questions as follows: (1) Strip marks are formed from the roll surface. (2) High temperature of roll surface cause burning phenomenon and lower the hardness of roll surface. (3) Cracks are formed on the roll surface. (4) There is a deflection of horizontal pipe of rocker arm. The improved pinch roll is called new pinch roll. The original pinch roll is called old pinch roll. First, temperature gradients of each location for the old pinch roll and the new pinch roll are calculated, and the reasons of the abnormal high temperature of roll surface are clarified. Second, for the places of the old and new pinch rolls which are the easiest to crack, its stresses of x-y and y-z directions are analyzed. Influence factors of thermal stress crack are clarified. It is proved that the thermal stress effects of the new pinch roll are less than the old pinch roll. Third, the relations of thermal deflection and heat convection for the original horizontal pipe of rocker arm and for the improved horizontal pipe are analyzed. Furthermore, according to the internal structure of the old and new pinch rolls, the flow resistance of circulating water cooling system for each place is considered. Finally, roll grinder is developed and designed to improve the quality of roll surface.