Abstract: In order to reasonably arrange field growth period of tobacco variety NC55, field experiments with three transplanting time treatments (04-25, 05-05, 05-15) were carried out to study the effects of transplanting time on the initiation process of tobacco leaves, to identify the relationship between effective accumulated temperature and leaf initiation, and to establish dynamic models. The results showed that transplanting time did not change the final number of leaves, but the dynamic change of leaf initiation was significantly affected by transplanting time. The initiation time of leaves was shortened as the transplanting time delayed. However, the effective accumulated temperature required for the initiation of middle and upper leaves had no significant difference among different treatments. The dynamic models of leaf initiation were established with high precision, as the R² values of all models were higher than 0.980. The transplanting time affected the dynamic process of leaves initiation mainly by controlling B, K and N values. The accuracy of the model with growth time as independent variable was better than that of the model with effective accumulated temperature as independent variable. The dynamic model of tobacco leaf initiation was an incomplete "S" type growth curve, which included slow growth period and rapid growth period only.