In order to study the rejuvenating effect difference of rejuvenation fluid on water tree ageing cable when different catalysts were combined with siloxane, we selected a methyl phenyl dimethoxy siloxane (PMDMS) and a long-chain siloxane, tetraisopropyl titanate (TIPT) and long-chain benzene sulfonic acid two catalysts to prepare four rejuvenation fluids with different formula. Water tree aged cables were rejuvenated by injecting the rejuvenation fluid and conducted second ageing, and their electrical properties and microstructure changes were analyzed by the power frequency breakdown test, water tree morphology observation, and FTIR test. The results show that four kinds of rejuvenation fluids can inhibit the growth of water tree, and the breakdown voltage of the water tree aged sample is improved. The rejuvenation fluid composed of long-chain siloxane and long-chain benzene sulfonic acid has the highest retention rate in the insulation layer, and the rejuvenating effect is the best. The rejuvenation fluid composed of PMDMS and long-chain benzene sulfonic acid has the lowest retention rate in the insulation layer, and the rejuvenating effect is the worst. It is proved that when the diffusion speed of siloxane and catalyst in insulation layer matches, the retention rate of the siloxane can be improved, and the long-term rejuvenating effect can be enhanced.