With the continuous advancement of technology, aeronautical thermal management has emerged as a hotspot of concern. The use of phase change materials in thermal management is also gaining attention, thus the melting performance under different gravitational conditions needs to be investigated. In order to gain further insight into the melting properties of phase change materials under multiple gravity conditions, we constructed numerical models which enabled us to evaluate a number of key metrics, including the complete melting time, heat storage capacity, phase interface, temperature, velocity distribution and other relevant factors. The results indicate that the total melting time is reduced when the gravitational force is increased. In particular, the complete melting time at a gravitational force of 5g is 62% shorter than at 1g. Furthermore, the thermal efficiency also exhibits an increase with the rise in gravitational force. Furthermore, the increase in gravity enhances the natural convective heat transfer in the phase change material, which is conducive to improving the heat transfer performance of the material, as can be seen from the velocity, temperature and phase interface distributions. This study provides a theoretical basis and reference significance for application in practical engineering.