The occurrence number of landslides due to heavy storms per unit area (250m*250m) is found to follow a negative binomial distribution with parameters k and p, in which the variance is greater than the mean. Taking note of the reproducing property of the parameter k against a same value of p, and taking account of the linear relationship between the mean number of landslides and the parameter k, an exponential regression model of k is proposed. The coefficients of the explanation variables of the regression model can be calculated by the maximun likehood method, and the confidence intervals of expectaions for the occurrence number and area of landslides are theoretically derived.