The condition monitoring and fault diagnosis method based on decomposed component analysis (DCA) for SF6 gas-insulated equipment, which mainly aiming at AC SF6 gas-insulated equipment, has become a research hotspot. Therefore, SF6 positive DC partial discharge (PD) decomposition experiments under four typical insulation defects were conducted in this work. The result showed that there is a significant correlation between the generation rules of the five SF6 decomposition components (CF4, CO2, SO2F2, SOF2 and SO2) and the types of defects. The phenomenon was attributed to the variations in the properties of the four insulation defects. In addition, comparing with AC PD experiment, for the protrusion, contamination and gap defect models, the amounts and generation rates of the five characteristic decomposition components under positive DC are less than those under AC by the same defect; however, for the particles defect, it is by contrary. This could be attributed to the essential difference between AC PD and positive DC PD. Therefore, the theory of AC DCA could provide reference to construct DCA diagnostic model for DC SF6 gas-insulated equipment, but cannot be applied mechanically.