A reactive dilution type of cold patch asphalt liquid was developed in this study using acrylate epoxidized soybean oil (AESO). The AESO was employed as a reactive diluent to replace a portion of conventional solvents. The curing of the cold patch asphalt liquid was facilitated through photoinitiation to enhance the road performance of the cold patch asphalt mixture. An orthogonal experimental design method was used to optimize the proportions of various components, followed by laboratory experiments to investigate the performance of the developed reactive dilution type of cold patch asphalt liquid. The research results indicated that AESO could replace a portion of solvents and significantly reduce the viscosity of the asphalt. The best improvement in the rheological properties of the cold patch asphalt was achieved when the dosage of AESO was 4%. Further increasing the dosage of AESO did not significantly enhance the performance improvement and instead increased viscosity, which was unfavorable for construction. SEM observations revealed the formation of a uniform network structure in the asphalt after curing with AESO, which can enhance the road performance of the cold patch asphalt mixture. The road performance of the reactive dilution type of cold patch asphalt mixture was also preliminarily evaluated through Marshall stability tests.