In this study, the hourly transpiration rate of Cinnamomum camphora was measured from June 2019 to October 2020 using the Grainer-type thermal dissipation probes. Meteorological factors and soil water content were simultaneously monitored during the study period. To deepen the understanding of the relationship between plant physiological changes and environmental changes, and to provide a basis for improving the accuracy of transpiration predicting model, this study analyzed the relationship between the transpiration of C. camphora and the main meteorological factors at different periods during the day. The variation characteristics of time lag and the change of hysteresis correction on the predicting model of transpiration were also investigated. The results showed that the time lag between transpiration and solar radiation is counterclockwise, and that between transpiration and saturated water vapor pressure or temperature is clockwise during the growing seasons (from June to October). Based on Gauss equations, it was found that on average transpiration in the growing seasons of 2019 and 2020 lagged behind solar radiation by 0.94 hours, and advanced by 2.60 and 2.61 hours on saturated vapor pressure difference and temperature. This time-lag effect was caused by the different responses of transpiration to meteorological factors at different stages of the day. In the rising stage (7:00-11:00), transpiration was more sensitive to changes of solar radiation than that in the descending stage (17:00-21:00). On the contrary, in the rising stage, transpiration was less sensitive to variation in saturated vapor pressure and temperature than that in the descending stage. The time-lag effects between transpiration and solar radiation or saturated vapor pressure or temperature had obvious seasonal variation. There were certain differences in the hysteresis loop area between the growing seasons of 2019 and 2020, but the maximum area appeared in October and the minimum area appeared in August or September. On the hourly scale, when soil moisture was sufficient, the hysteresis added with the increase of the main daily mean meteorological factors, but under soil moisture stress, the time lag did not change significantly with the increase of the major daily mean meteorological factors. After correcting time lag, the determinants of the regression equations of transpiration and solar radiation increased by 4% and 9%, and the coefficient of determination of the regression equations of transpiration and integrated meteorological factors constructed by principal component analysis increased by 7%. Therefore, eliminating time lag could improve the accuracy of transpiration predicting model.