This study introduces an innovative strategy, termed the "epoxidation & combination" approach, to create cost-effective and mechanically enhanced 3D printing photocurable materials by using waste cooking oil (WCO) as raw material. Within this strategy, WCO is first subjected to epoxidation, yielding epoxy waste cooking oil (E-WCO). Subsequently, E-WCO is combined with triethylene glycol dimethacrylate (TEGDMA) to formulate a E-WCO plasticized TEGDMA photocurable resin suitable for 3D printing. Functioning as a plasticizing component, E-WCO effectively resides within the TEGDMA substrate with minimal migration (0.30% at 135℃ for 24 hours). Furthermore, appropriate addition of E-WCO significantly enhances the mechanical properties of the TEGDMA-based resin, especially in terms of toughness. The optimized composition of the E-WCO/TEGDMA 3D printing resin, with an E-WCO : TEGDMA mass ratio of 1:15, demonstrates exceptional mechanical strength. This includes a tensile strength of 16.74 MPa, an elongation at break of 32.93%, and an impact strength of 3.94 kJ/m2, surpassing the benchmarks of pure TEGDMA. When compared to commercial epoxy soybean oil (ESO), E-WCO provides an equivalent plasticizing effect, effectively enhancing material flexibility. The transformation of WCO into the E-WCO/TEGDMA resin not only promotes the high-value utilization of WCO but also holds significant potential for developing low-cost and sustainable 3D printing consumables.