1. A ball pitching device, comprising a frame, an upper polyvinyl chloride (PVC) sheet and a lower PVC sheet, wherein the upper PVC sheet is connected with the frame, the lower PVC sheet is located below the upper PVC sheet, the lower PVC sheet is connected with the upper PVC sheet, a ball storage space is formed between the lower PVC sheet and the upper PVC sheet, the upper PVC sheet is configured with a hole, wherein the frame comprises three first elbows and four second elbows, the three first elbows are connected in sequence, two adjacent ones of the three first elbows are arranged horizontally and hinged to each other, a remaining one of the three first elbows extends obliquely and is hinged to one of the two adjacent ones of the three first elbows arranged horizontally, wherein two of the four second elbows are respectively hinged with the two adjacent ones of the three first elbows arranged horizontally at two ends of the frame, another one of the four second elbows is hinged at a connection between the two adjacent ones of the three first elbows arranged horizontally, and a remaining one of the four second elbows is hinged to the remaining one of the three first elbows.