The invention mainly relates to an automatic cloth measuring machine. The automatic cloth measuring machine mainly comprises a main frame, wherein a cloth returning mechanism, a cloth guiding roller I, a driving roller, a conveying belt device I, a platform board and a conveying belt device II are sequentially arranged on the main frame along the feeding direction of cloth; the cloth returning mechanism comprises two cloth returning rollers, and the two cloth returning rollers are horizontally installed on the main frame; the driving roller is driven by an independent driving device, and the driving roller is used for feeding the cloth and enables the cloth to fall on the conveying belt device I; a photoelectric sensing controller I is arranged on the main frame on the position, on the side of the driving roller, of the main frame, a sensing plate is arranged at the position, corresponding to the photoelectric sensing controller I, on the other side of the main frame, and the photoelectric sensing controller I is obliquely arranged with the sensing plate; and the photoelectric sensing controller I is used for sensing the cloth falling from the driving roller and controlling the feeding speed of the driving roller, the lower end of the platform board is provided with a measuring wheel, the measuring wheel is used for measuring the length of the cloth, and the conveying belt device I and the conveying belt device II are synchronously rotated. The machine has the advantages that the design is ingenious in structure, the cloth can be measured in a natural state, the cloth measuring is accurate, and the metering efficiency is high.