The invention provides a method for improving the gasifying dephosphorization effect through bottom-blowing powder spraying of a converter. The method for improving the gasifying dephosphorization effect through bottom-blowing powder spraying of the converter specifically comprises the steps that after steel is discharged out of the converter, the basic state of converter slag is observed and judged, slag-splashing converter protection operation is started, and gasifying dephosphorization powder is sprayed into the converter through a carrier gas nozzle at the bottom of the converter at the same time; the bottom-blown carrier gas pressure and the powder-gas ratio of the converter are controlled, so that the gasifying dephosphorization powder efficiently reacts with hot slag in the converter under the surging and stirring effect achieved when the carrier gas penetrates through the converter slag; and phosphorus in the slag is removed in a gasifying mode, the slag is converted into gasified and dephosphorized high-quality slag after the reaction and is used for the next round of converter smelting. The gasifying dephosphorization rate of the converter is 50%-60%, the penetration ratio of the dephosphorization powder is 80%-90%, and lime consumption is reduced by 2.5-3.5 kg/t. According to the method for improving the gasifying dephosphorization effect through bottom-blowing powder spraying of the converter, the strong surging and stirring function and other functions of the gasifying dephosphorization powder and the carrier gas are brought into full play, the gasifying dephosphorization rate is increased, the slag-splashing converter protection cycle is shortened, and the utilization rate of left converter slag is increased. The bottom-blowing dephosphorization powder is not prone to being carried away, the operating condition and distribution of the powder in the hot slag are improved, and the utilization rate of the powder is increased.