A symbolic transitional semantics for value—passing process algebras is proposed and the notion of symbolic bisimulation is introduced．It is proved that two process-es are bisimilar in the traditional sense if and only if they are symbolicaly bisimilar．Since the transition graphs of value—passing processes over infinite data domains are infinite，while the symbolic transition graphs of many such processes are finite，the article'S result makes it possible to decide bisimulation—based equivalences for such these processes in fi-nite amount of time and space．