The invention discloses an iron mould coated sand oil cylinder tool which comprises a datum plane, wherein a square iron mould is arranged on the datum plane; a plurality of oil cylinder casting cavities are formed in the iron mould and are connected with a gating system; and the gating system is connected with a sprue cup. According to the technical scheme provided by the invention, through adopting the iron mould coated sand moulding process, a casting is less in machining allowance, high in technological yield, compact in texture and of high quality, and the mechanical property and particularly the pressure-resistant property of the casting meet the requirements.