The work aims to propose a cylindrical phase change heat storage rod (PCM-rod) according to the encapsulation structures of phase change materials in solar thermal utilization and design multi-angle fins to accelerate the melting rate of phase change materials. The effects of different shapes of fins on the melting characteristics of the phase change material in the heat storage rod was analyzed by CFD simulation technology, and the melting time, temperature response rate and average heat transfer coefficient of each model phase change material were calculated. The calculation results under the heat flow boundary condition of 800 W/m2 showed that it took 2 813 s to completely melt the phase change material in the PCM-rod without fins, and the Tra-45 model had the best performance among the 12 groups of fins designed. The melting time of the phase change material was shortened by 5.4% compared with the control without rib. The temperature distribution of the phase change material in the Tra-45 model was concentrated, and the maximum temperature increased by 6 °C. The temperature response rate of the Tra-45 model was increased by 5% compared with the control group, and the average heat transfer coefficient reached 9.97 W/(m2.K), which was 2.8% higher than that of the control group. After the trapezoidal 45° fins are added to the heat storage rod, the melting rate of the phase change material is accelerated, and the temperature distribution in the heat storage rod is uniform. At the same time, the temperature response rate of the phase change material is improved, and the average heat transfer coefficient is significantly increased, which can meet the needs of frequent heat charging/release of the phase change material.