We　have　unified　quantum　and　classical　computing　in　open　quantum　systems　called　qACP　which　is　a　quantum　generalization　of　process　algebra　ACP.　But,　an　axiomatization　of　quantum　and　classical　processes　with　an　assumption　of　closed　quantum　systems　is　still　missing.　For　closed　quantum　systems,　unitary　operator,　quantum　measurement　and　quantum　entanglement　are　three　basic　components　of　quantum　computing.　This　leads　to　probability　unavoidable.　Along　the　solution　of　qACP　to　unify　quantum　and　classical　computing　in　open　quantum　systems,　we　unify　quantum　and　classical　computing　with　an　assumption　of　closed　systems　under　the　framework　of　ACP-like　probabilistic　process　algebra.　This　unification　make　it　can　be　used　widely　in　verification　of　quantum　and　classical　computing　mixed　systems,　such　as　most　quantum　communication　protocols.