In order to shorten the small arms products development period, a new model of digital parallel cooperative development of small arms is proposed to meet the needs of distributed collaborative development. Use the advantages of network and information technology, according to the current development situation of small arms, change the traditional development mode, and establish the small arms digital cooperative research model. Realize the resource sharing use, introduce the theory of parallel engineering and maturity, conclude the operation steps of small arm digital cooperative development mode, and put forward the new mode for small arm parallel cooperative development. The application results show that the mode can improve the product research efficiency, and provides reference for 3D design of small arms cooperative development.