VIBE algorithm in intrusion detection under complicated background environment along the railway has obvious problems.In the VIBE algorithm parameter is fixed, cannot the auto-adapted background change;When the train passed the "ghost" phenomenon exists for a long time;Detected targets have the cavity.An improved VIBE algorithm.The algorithm can change the auto-adapted parameter according to the background;Switch to special mode when the train passed;Morphological processing for detection of moving targets. Test results show that,improved VIBE algorithm is well adapted to the complex background environment along the railway, and in real time and high robustness.