This paper presents a method for tracking multiple moving objects with invehicle 2D laser range sensor (LRS) in a cluttered environment, where ambiguous/false measurements appear in the laser image due to observing clutters and windows, etc. Moving objects are detected from the laser image with the LRS via a heuristic rule and an occupancy grid based method. The moving objects are tracked based on Kalman filter and the assignment algorithm. A rule based track management system is embedded into the tracking system in order to improve the tracking performance. The experimental results of two people tracking validate the proposed method.