The invention discloses a start control method of a power station drum boiler. According to the method, after a normal water level is reached by feeding water into the boiler, firstly boiler body blowoff valves and boiler body drain valves are closed before ignition; and then a high-pressure bypass adjusting valve is fully opened, a low-pressure bypass adjusting valve is opened to a preset openingdegree, a vacuum system is utilized for reducing the pressure of a steam pocket, superheaters and reheaters to the vacuum state, the saturation temperature of boiler water is decreased, the densitiesof air in all heating surface pipelines are decreased, accordingly, the air resistance in the pipelines is decreased, pressure required for steam flowing is reduced, and steam flowing is smoother. Steam produced by the boiler passes through the boiler superheaters, a high-pressure bypass, reheaters and a low-pressure bypass in sequence to enter a condenser or a steam exhaust device, the steam enters the boiler superheater and reheater heating surfaces at the same time, the dry ashing time of all the heating surfaces is shortened, the safety of metal of all the heating surfaces is guaranteed,the risk of leaking of the heating surfaces is lowered, meanwhile, exhausted steam during start of the boiler is recovered, wasting of water resources is avoided, and the purpose of working medium recovery is achieved.