Conversion rubber track assembly is used for the replacement of the wheeled vehicle tire to reduce the vehicle’s ground pressure and improve its offroad performance. It is composed of a wheel system and a rubber track. In order to avoid detracking and excessive tension of the track and make the track perimeter match the wheel system, a modeling method of rubber track perimeter is developed which is based on variations in relative location of each wheel of the wheel system. In this method, the track perimeter is divided into two kinds of segments, circular arc segment that is in contact with wheels and deformation segment which does not contact with wheels. If a deformation segment does not contact with the raised obstacle, then it is a straight line, otherwise it is a circular arc. The effect of the roller wheel swing on the perimeter of the track is studied and the matching tensioning device is designed to maintain the track perimeter constant while roller wheels swing. Under multiterrain conditions, multicamera videogrammetric system is used to track feature points on each wheel of the wheel system and coordinates of feature points are collected to reconstruct the axis of each wheel, and then the track perimeter is modelled. Experimental results on a flat steel plate show that because of the uneven track bending stiffness, the modelled average perimeter of the track is 3791.62mm with standard deviation of 3.51mm, which is slightly smaller than the actual perimeter 3812mm of the track. Experimental results under multiterrain conditions are consistent with those on a flat steel plate, the standard deviations are all about 3.5mm and the average perimeters of the track are all in the range of 3787.78mm to 3794.75mm. Therefore, this modeling method of rubber track perimeter is effective, robust, free from the impact of terrain, and it also provides the basis for the design and assessment of the rubber track assembly.