The invention relates to the technical field of automatic control of thermal power units, in particular to an optimization control method for improving the reliability of unit bypass heat supply operation. The method comprises the following steps that when a heat supply thermal power generating unit is in a bypass heat supply mode, the fault of the unit bypass heat supply system is judged throughconfiguration of a control logic of a DCS of the heat supply thermal power generating unit; the size of bypass heat supply steam flow is judged, and interlocking protection action is performed in combination with fault of unit bypass heat supply system, so that the safety and stable operation of the unit is ensured; an automatic control logic is added, and the stability of operation parameters ofthe unit bypass heat supply system is controlled; and historical operation data and design data of the DCS of the heat supply thermal power generating unit are inquired, and all automatic control logic parameters are set. According to the method, the safety of equipment can be guaranteed under the working condition that the heat supply quality is ensured by the heat supply unit, the labor intensity of operators is effectively reduced, the control effect is not dependent on the technical level of operators, the real-time performance is good, the field debugging process is simple, and the engineering is convenient to realize.