The invention discloses a steel roof aluminum skirt piston machining process, which comprises the following steps of: a, performing rough turning on a head and an excircle, and performing rough turning on a seam allowance and the excircle; b, roughly boring a pin hole, and milling the radius; c, performing finish turning on the seam allowance, milling a central hole, and performing semi-finish turning on the excircle and a top surface; d, performing semi-finish boring on the pin hole; e, boring the inner distance; f, checking the shape of an inner cavity; g, drilling; h, milling a spherical surface of a counter bore; i, drilling an oil return hole; j, turning a lock groove, and turning chamfering of the pin hole; k, milling an oil groove of the pin hole; l, performing finish boring on the pin hole; m, imitating an ellipse; n, turning holes and chamfering; and o, forming fitter chamfering, removing burr and flashing, and cleaning. By the steel roof aluminum skirt piston machining process, the machining accuracy is high, the process flow is precise and the quality of the machined product is high.