Abstract: Trackless auxiliary transport vehicle had many kinds and custom types products, that brought variety subdivision vehicle and gave cause for a great deal of parts, non-interchangeable parts and difficult production organizing. In order to solve the above problems, modularized design method was proposed. By analyzing the structure style and system composing of trackless auxiliary transport vehicle, this paper proposed built some product platform between relative type of vehicle, which was adopted to carry on modularized design. Besides, detailed modularized design way and method was present, and process of modularized design was introduced by taking the gate roadway vehiclethe for example. In the end, the connected method between different system module of the vehicle was father expounded, the universal design of assembling interface was discussed.