A new tape resistance welding power source based on 80C196KC single-chip microcomputer was developed.The MOSFET group worked at linear state was used as current adjuster.Arbitrary control of current waveform was achieved first in the moment of resistance welding.So that it is possible to weld with optimal current waveform in resistance welding.The power source was used in the welding of bridge band,that solved the problem occurred at traditional welding means,and met the strict requirement of the welding quality of bridge band.The practice shows that it is an ideal power source in the precise welding of minisize metallic workpiece.