Flux for improving melting performance of coal ash for blast furnace injection and use method

The invention relates to a flux for improving the melting performance of coal ash for blast furnace injection. The flux is prepared by respectively grinding and mixing steel slag powder, fly ash, quick lime and calcium-containing stone as raw materials. The raw materials comprise 20%-70% of steel slag powder with the granularity less than or equal to 8mm; 10-40% of fly ash with the granularity less than or equal to 5mm; 5-20% of quick lime with the granularity less than or equal to 5 mm; and 10%-40% of calcium-containing stone with the granularity less than or equal to 6mm. The flux for improving the melting performance of the coal ash for injection at low cost is processed and manufactured by utilizing a secondary product of an iron and steel plant so that the melting performance of the coal ash for blast furnace injection can be remarkably improved, and after the technical scheme is adopted and the flux is added, a large amount of low-cost pulverized coal can be added, the range of the coal for injection is