The invention discloses a yarn positioning device for knitted cap production special yarns. The yarn positioning device is arranged at the top of a knitting machine, and comprises a fixing seat and across beam frame, wherein the fixing seat is of a hollow structure, a deceleration motor is arranged on the surface of the fixing seat, an output shaft of the deceleration motor penetrates through thefixing seat to be provided with a driving wheel, a plurality of bearing blocks are arranged at the top end inside the fixing seat, and bearings are arranged in the bearing blocks; and a rotating baseis arranged in the inner ring of each bearing, two belt grooves are formed in the lower end of each rotating base, a driving belt is arranged in the belt grooves, every two adjacent rotating bases are connected through the driving belt, the one rotating base close to the deceleration motor is in transmission connection with the driving wheel through the driving belt, the deceleration motor can drive the rotating bases to rotate on the fixing seat through the driving belt, the upper ends of the rotating bases penetrate through the top end of the fixing seat, a positioning column is verticallyarranged at the center of the top of each rotating base, the top ends of the positioning columns are provided with openings, and the openings of the positioning columns are in threaded connection withlimiting covers, so that a yarn barrel is limited and fixed.