Abstract: With the data obtained from inoculation experiments,the apparition dynamic of asparagus long bean(Vigna sesqurpedalis(L.)Fruvvirth)rust(Uromyces phoseoli Wint var.Vignae(Barcl.)Arth)was studied in detail,showing that Richards function was the best for the description of the apparition dynamic and there was no singificant difference between Logistic and Gompertz functions.As a unit,the effective accumulated temperature was found to be better than day for the study of the probability of apparition of this fungus no matter which function was used.The method for determining the latent period of the disease by the use of inflexion of the function was described,the latent period of the disease studied being found to be 7-9 days.