The invention relates to whole digit time sequence adaptability control method of the CO2 welding. It is used in the welding technique field. The control method in the CO2 welding power system is practiced to realize the full digital time sequence adaptability adjusting control of the dead full short circuit transient process. The control method of the DSP digital control CO2 welding power includes the overall process digitization time sequence adaptability adjusting control for the CO2 short circuit transient welding, practicing adaptability adjusting to unceasing change of the dry extension of electrode in the handwork semi automation welding process to ensure the stability of the welding process, practicing instantaneous short circuit control while entering the high level interrupt program of the DSP, short circuit current di/dt control in the short circuit stage, and full digital time sequence control in the short circuit transient process. The features of the invention are that the splashing is little, and less then three percent; the formation of weld is beautiful; it has good adaptability to the change of the dry extension of electrode and the disturbance of the arc length; and its adjusting is convenient; the range of the applicable welding current is wide; and it can gain good effect in the range from sixty A to two hundred and eighty A.