The invention discloses an air cylinder cover bolt screwing process. The process includes the following steps: (1), pretightening, namely using a first screwing tool to enable pretightening moment of air cylinder cover bolts to become initial moment by tightening; (2), marking a starting point, namely selecting any side edge on an air cylinder cover bolt head as a rotating reference edge, and marking a rotating reference mark and a starting point mark on the side edge and a position, corresponding to the side edge, on the top surface of an air cylinder cover at the same time through a marking tool; (3), marking an end point, namely by taking the rotating reference edge as a starting point, calculating an end point position where the corresponding rotating reference edge is positioned after each air cylinder cover bolt is screwed, and marking an end point mark at a corresponding position on the top face of the air cylinder cover; (4), tightening, namely screwing the air cylinder cover bolts through a second screwing tool to enable the rotating reference edges of the air cylinder cover bolts to rotate to positions corresponding to the end point marks. The air cylinder cover bolt screwing process is accurate in rotating angle, needless of other detecting and measuring tools, simple in operate and high in practicability.