The forming process of wire and arc additive manufacturing (WAAM) based on the cold metal transfer (CMT) is studied. By monitoring the arc shape, current signal and molten pool shape, the characteristics of droplet and the stress of molten pool metal in different stages of arc are studied. Based on the investigation on the force of the molten pool metal in the forming process of the suspensed structure, the propeller was manufactured and the microstructure and properties were also analyzed. The results show that the rapid prototyping of suspension structure and good mechanical properties can be obtained by precise control of Ibase and Ibase/Ipeak during the CMT process. Under the conditions of this study, the form of short-circuit transfer is the main metal transfer during CMT additive of titanium alloy, and there is no droplet transfer in the peak stage. When Ibase/Ipeak is less than or equal to 0.2, the cantilever structure with large inclination can be obtained by reducing the base current, and the maximum inclination angle of Ti6321 propeller manufactured by CMT process is 53.26°. The Ti6321 alloy fabricated by the optimized overlapping parameters has dense internal structure and no coarse columnar crystals penetrating multiple layers are found in the part. The mechanical properties of the AM parts are the same as the standard of forging, and the anisotropy between horizontal and vertical is not obvious.