The object possesses inherent parallelity. Combination of object-oriented programming with distributed-parallel processing will bring about object-oriented distributed parallel system, not only having object-oriented property but also making better use of system resources and shortening user's computing time as well. In this paper, a novel C++ object distributed-parallel mechanism is proposed based on PVM (parallel virtual machine). The object distributed-parallel mechanism is supported by the PVM system whose protocol and pvmlib have been made backward compatible extension. It uses preprocessor to separate the parallel-classes from user's job program and dispatches them to host computers in PVM to compile and run there. Through mapping parallel-class to PVM task, request object message to request PVM task message, the mechanism implements object distributed-parallelism of the parallel-class. The results of the experiment show that (when the size of question is big enough) the mechanism may make better use of the system resource, run user program efficiently, and simplify the PVM application programming.