In order to explore the tolerance of Glyptosternon maculatum to extreme temperatures at different stages, this study performed acute hyperthermic stress on the fry and adult fish, determined semi-lethal time at each temperature, and measured the respiratory rate of adult fish under hyperthermia. The results showed that the semi-lethal time (LT₅₀) of fry G.maculatum shortened with the increase of temperature, and there was a significant difference in the LT₅₀ of the different temperature groups (P<0.05), among which LT₅₀ was 13.53 h at 28 ℃ and 71.20 h at 24 ℃. The respiratory rate of adult fish under high temperature stress increased significantly, and the semi-lethal time (LT₅₀) of adult fish at 24 ℃ was 15.6 h, which was much lower than that of fry at this temperature. The results showed that there were differences in heat tolerance at different growth stages, and attention should be paid to water temperature control during the breeding process. The short-term lethal temperature of fry was 28 ℃, and the short-term lethal temperature of adult fish was 24 ℃. The results of this study can provide basic data for healthy breeding and further study of high temperature tolerance mechanism of G.maculatum.