Field experiment was conducted to study the dynamic changes of chlorophyll content and SPAD data during maturity stage of tobacco leaves. The relationship among chlorophyll content and SPAD data and time were analyzed in this study. The results showed that both the relationship between chlorophyll content and time and the relationship between SPAD data and time could be described by linear equations at p < 0.01. The equations could be used as the predicting model of the maturity time of tobacco leaves. The predicting accuracy was described with the proportion of the simulated results obtained into the maturity time range. The maturity time ranges were calculated by using quadratic function based on observed results in field. When the time of = 70% leaves in field properly matured was used as the maturity time range, the predicting accuracy based on chlorophyll content and SPAD data was 62.5% and 75% respectively. The prediction based on SPAD data was more accurate than that based on chlorophyll content. The results also showed that the proper measurement location of SPAD data was about 50% from the base to the tip of tobacco leaves.