The invention discloses technology for casting a transfer case casing of a concrete pump truck through an aluminum alloy, which comprises the following steps: (i) core moulding, (ii) gravity casting, (iii) casting clearing, (iv) quenching and seasoning, (v) shot blasting and finishing, (vi) oil removing and (vii) machining. According to the invention, the transfer case casing is cast by a gravitycasting technology which takes a ZL111 aluminum alloy as a raw material, thereby having good heat conduction property and excellent machining performance; and the mechanical property of the transfer case casing is good, particularly the tension strength is greater than or equal to 320MPa, the elongation is grater than or equal to 2%, and the hardness is greater than or equal to 100HB.