The utility model relates to an energy -conserving field in power plant discloses a generating set waste heat residual pressure uses multipurposely device, generating set waste heat residual pressureuses multipurposely device includes main steam turbine (1), back pressure type small steam turbine (2), condenser (3) and heat pump (4), main steam turbine draw gas the export with back pressure typesmall steam turbine's steam inlet intercommunication, back pressure type small steam turbine's steam extraction leads to the heat supply network heat exchanger, main steam turbine's exhaust steam export with the condenser intercommunication comes from the cooling water of condenser is in heating heat supply network return water in the heat pump, heat supply network return water after the heating lead to the heat supply network heat exchanger, back pressure type small steam turbine with the heat pump electricity is connected. This generating set waste heat residual pressure uses multipurposelydevice has reduced throttling loss, has improved the cascade utilization level of energy, simultaneously, realization used heat is recycled, has improved the heating capacity of unit.