This paper describes the development of a Cloud-based solid cutting simulation service system for 3D toolpath verification before it is to be uploaded to a CNC machine tool for machining operation. A user can access the system through common WWW browsers such as Internet Explorer and/or Google Chrome in either a PC running Microsoft Windows, a smart phone running Android, or an iPad running iOS. The system can perform real time solid cutting simulation based on the toolpath (NC program). The system provides user with standard views such as 'ISO View', 'Front View', 'Right View', and 'Top View'; dynamic customized 3D view could be controlled through the mouse operation on the client side to ease the visibility during the simulation. The proposed system has been successfully implemented on a public cloud system Microsoft Azure with expected performance and is expected to assist a user in verifying the correctness of the toolpath and to enhance the efficiency in a geographically dispersed networked environment.