A method to simulate the leaf color based on SPAD data was presented. Firstly, the color data in different physiological ages of green dill leaves were tracked and detected using a self-made device for capturing leaf images, which could maintain the stability of the external environment (such as light, camera position). Then, the leaf color attributes were analysed based on the data collected and a function representing the relationship between SPAD and leaf color was constructed to deduce the diffuse reflection formula of the leaf. Finally, a SPAD texture was used to simulate the time-and-space-varying reflectance of leaves aging. The experimental results showed that in the constant environment, the relationship between the SPAD and diffuse color of leaves could be represented by some exponential functions and the R2 was 0.972，0.968，0.509 respectively. This showed that there was a correlation between SPAD and leaf diffuse color, and it was reasonable using SPAD value as a driving factor to simulate the leaf aging. Meanwhile, compared with real photo, visual effects of proposed method could show the trend of leaf color aging realistically.