Abstract: Focused on the issues of poor thermal stability and narrow processing window of CPVC resin served as the matrix material for high-voltage cable laying CPVC protective sleeves, the formulation of sleeves were designed and optimized under the condition of established processing technology to improve product quality. The results showed that 4.5% mass fraction calcium-zinc composite stabilizer with 1.1% calcium stearate effectively enhanced thermal stability, improved surface appearance, and increased impact resistance. The composite system of 0.8% internal and 1.2% external lubricants improved the processing fluidity of the blend and enhanced the ring-section compressive strength of the sleeves under thermal conditions. Synergistic toughening with 6% methylmethacrylate-butadiene-styrene (MBS) and 3% chlorinated Polyethylene (CPE) yielded the maximum notched impact strength. The addition of 1.8% acrylic copolymer (ACR) impact modifier facilitated plasticization of the blend and improved the surface quality of the sleeves. Furthermore, 15% activated calcium carbonate was used as a filler to maintain the material performance while reducing production costs. Finally, The inclusion of 16% PVC resin met the standard requirement of a Vicat softening temperature above 93°C and reduced raw material costs. Through the synergistic optimization of the multi-additive system, an effective approach was provided for the formulation design of CPVC protective sleeves.