The architectures (including two out of three architecture and double 2-vote-2 architecture) of three types of generic vital computer which used in railway traffic signaling system at present were introduced, and the requirements of the internal time synchronization of vital computer were analyzed. Based above, two models of internal time synchronization were built and corresponding solutions were raised, which were verified by the internal synchronization of vital computer with two out of three architecture and double 2-vote 2 architecture. The result demonstrated that the two kinds of solutions could make the accuracy of internal synchronization in vital computer less than 2 milliseconds, which met the needs of most railway traffic applications.