The invention relates to the technical field of automatic control methods, in particular to a bypass system comprehensive control method for improving the adjusting capacity of a heat supply unit. Thebypass system of the heat supply unit is comprehensively controlled, so that the adjusting capacity of the heat supply unit is improved. The control method comprises the following steps that the bypass system comprises a high-pressure bypass system and a low-pressure bypass system; it is judged that the heat supply unit is in a bypass heat supply mode; it is judged that the heat supply unit exitsthe bypass heat supply mode; the control logic of each valve of the high-pressure bypass system is optimized respectively; the control logic of each valve of the low-pressure bypass system is optimized respectively ; control logic configuration is carried out on the DCS of the heat supply unit, the control logic of the DCS of the heat supply unit is optimized and adjusted, and the adjusting capacity of the heat supply unit is improved. According to the bypass control system of an existing unit DCS (distributed control system), the control method is good in real-time performance, simple in field debugging process and convenient for engineering realization.