Weld bead geometry and porosity of AA2219-T851 high strength aluminum alloy welds with ER2319 wire produced by different cold metal transfer (CMT) processes and its heat input were investigated. The results show that, a narrow finger-shaped geometry is observed using the conventional CMT process and a large number of gas pores exist in the lower and upper part of welds. Compared to that of CMT process, the weld melting area is increased using CMT-P process, and it is beneficial to reduce the porosity effectively with an appropriate heat input. Finger-shaped geometry with lower melting depth using CMT-ADV process and spherical-shaped bead geometry with lower dilution using CMT-PADV process is achieved, respectively. The gas pore is reduced predominantly and even eliminated due to the lower heat input and effective oxide cleaning of wire ends for the two processes.