Abstract: A kind of personel illegal gathering imagine detection is given out in this paper. Some Gaussian models were obtained in a descending order according to the reliability measurements. The front Gaussian distribution was used to describe the background distribution. The prospect area was thought as a parameter of the personel illegal gathering image detection model. The original prospect area fornula was normailzed, and 2 D entropy was caculated by the 2D joint probability density. The scene was divided into some grid statistical intervals. All prospect probability density was caculated. On the basis of Shannon entropy theory, the 2D joint distribution entropy was obtained and the peronel illegal gathering detection model was constructed. The simulation results show that the proposed method is of high precision.