The conventional Logistic equation fails to accuratelt describe the variation in growth of soybean irradiated with UV-A/B（280～400 nm）radiation.Based on simulations,analysis and statistics are carried out,leading to mathematical models for better describing the growth exposed to a range of vigor(0.1,0.15,0.35 and 0.75 W·m^-2).Evidence suggests that Logistic equation is preferential for the growth of the crop under natural illumination while Gompertz formulation is appropriate for the development under stronger UV irradiation.