Model-Based Systems Engineering (MBSE) and the Systems Modeling Language (SysML) have become one of the best way to develop the design of complex equipment systems. The current modeling tools are all stand-alone. However, the system design of complex equipment is a complex task that requires the collaboration of experts from different disciplines and fields. The Web-based collaborative modeling method has always been a prioritized option because it has many advantages, such as “light” client, convenient maintenance, high model reliability, etc. However, how to implement the Web-based collaborative SysML modeling has always been a challenge. In this study, a Web-based collaborative SysML modeling method proposed for model-based systems engineering. First, the architecture of the Web-based collaborative SysML modeling platform is designed, and solutions for two collaborative scenarios of asynchronous collaboration and synchronous collaboration are also given. Secondly, through the application scenario analysis of asynchronous collaboration, the mechanism of authority management and access control which is suitable for the SysML model is proposed to realize security control of the model data. Then, the key technology of the SysML real-time collaborative modeling system is studied, and the problems of graphical collaborative editing concerned graphics concurrency control and consistency maintenance are solved. Finally, a prototype system for Web-based SysML collaborative modeling is implemented and a case study is given to demonstrate the effectiveness of the proposed method.