The invention relates to a method for manufacturing multi-purpose polyester fancy complex yarn through the change of a transversely moving cylinder. The invention solves the problem that fancy color with the combination of the light colored strips of various lengths and brightness can be dyed on the multi-purpose complex yarn with the functions of moisture absorbency and sweat transport, good airpermeability, ultraviolet ray protection and flame resistance. The important procedures of the method comprise the followings: on the false twisting machine with a double feeding system, a transversely moving cylinder (1) and a transversely moving yarn guiding frame (3) which are controlled by a programmable controller (PLC) are arranged between a zero roller (4) and a first roller (8), and an upper yarn guiding device (7) and a lower yarn guiding device (5) are arranged on the transversely moving yarn guiding frame (3); a hot ingot (6) is arranged on the false twisting machine; according to the preset time interval, the programmable controller (PLC) controls the transversely moving cylinder (1) and the transversely moving yarn guiding frame (3) to perform transverse reciprocating movement, so as to cause the strand silk to be contacted with the hot ingot (6) for being heated and stretched, or disengaged the contact.