Moving object detection is one of the most important tasks in intelligent visual surveillance systems. Gaussian Mixture Model (GMM) has been most widely used for moving object detection, because of its robustness to variable scenes. However, to the best of our knowledge, existing GMM based methods can not detect moving objects which gradually stop and keep still state for a while. In this paper, we present an Enhanced Gaussian Mixture Model, called EGMM, to handle this problem. We integrate an Initial Gaussian Background Model (IGBM) and an extended Kalman filter based tracker with GMM, to enhance its performance. Experimental results show that our EGMM based method has a lower miss rate at the same false positives per image comparing to GMM based method for moving pedestrian detection, and it also has a higher detection rate for abandoned object detection comparing to GMM based method.