The cold-constitutional and the heat-constitutional type had selected in Wistar rats as the object of study. Using peripheral blood and spleen as materials by means of ultraviolet injury, isotope incorporation, cells incubation in vitro and liquid scintillation counting, the capacity of peripheral lymphocytes DNA replication after damage with ultraviolet radiation and the capacity of the spleen lymphocytes proliferation in vitro was observed. The results showed that the both capacities mentioned above were higher in the heat constitutional type rat than that in the cold type. It is suggested that the following conclusion in the Lingshu Jing is correct: "the capacity of tissue repair is higher in the heat constitutional type than in the cold."