The invention relates to a counting overlock sewing machine. The counting overlock sewing machine comprises a rack. Installing bases are arranged on two opposite angles of the upper end of the rack. A bendable rail is arranged on the rack, and the two ends of the rail are connected with the two installing bases respectively. An upper roller is arranged at the upper end of the rail, and a lower roller is arranged at the lower end of the rail. A cross beam penetrates through the middle of the lower roller in an inserted mode, and the cross beam moves along with the lower roller. Overlock sewing devices for carrying out overlock sewing on cloth symmetrically placed on the rack are arranged at the two ends of the cross beam, and the overlock sewing devices slide in the axial direction of the cross beam. A counter is arranged on one side of the rack. Compared with the prior art, when an operator performs overlock sewing, it is only needed to place the cloth obtained after overlock sewing on the counter for induction, the cloth obtained after overlock sewing can be counted, counting is convenient, and overlock sewing efficiency is improved.