The invention belongs to the field of engineering machinery, and particularly relates to an integral casting digging bucket and a manufacturing method thereof. The integral casting digging bucket comprises a lifting lug, a top plate, two side plates and a bottom plate connected with the two side plates, and the lifting lug, the top plate, the two side plates and the bottom plate are integrated. Cast steel for casting the digging bucket comprises the following components: 0.1%-0.6% of C, 0.2%-0.6% of Si, 0.5%-1.8% of Mn, 0.5%-1.6% of Cr, 0.2%-0.75% of Ni, 0.1%-0.6% of Mo, less than or equal to 0.035% of P, less than or equal to 0.035% of S, and the balance of iron. The method for manufacturing the integral digging bucket of an excavator by using the cast steel comprises the following steps: smelting the components of the cast steel in a smelting furnace; and after smelting is finished, carrying out modification treatment in front of a furnace, manufacturing models and mould plates, coating, heating, vacuumizing, placing a sandbox, adding sand, modeling, carrying out mould assembling, pouring, quenching, and tempering and cooling to the normal temperature to finish casting of the digging bucket. A vacuum sealing technology and a low alloy steel material are adopted, the integral casting digging bucket is formed by one-time pouring, and the product is high in strength, high in wear resistance, corrosion resistance and impact force resistance and long in service life.