Sterling formula x0d has important theoretical and applied value, and is also of great significance to the development of probability theory. In mathematical analysis, most of them use г function, series with parametric variables, integral and other knowledge to prove or deduce, which is very complicated. In recent years, some scholars at home and abroad have proved it by using exponential distribution, Poisson distribution and X 2 distribution in probability theory. \x0d\\x0d\lim(n→∞)n！ /[n (n+1/2) * e (-n)] = √ (2π) \ x0d \ that is lim (n →∞) √ (2π n) * n * e (-n)/n! = 1