The melting of ice crystals in the compressor leads to ice formation on the blades. It is of great significance to analyze the ice crystal melting characteristics to study the ice crystal icing in the compressor. Based on the one-dimensional aerodynamic characteristics of the compressor, a rapid method for calculating the ice crystal melting ratio was developed and validated. A low-pressure compressor of a turbofan engine with a large bypass ratio was selected to study the influence of ice crystal size and ambient temperature on the ice crystal melting characteristics at the same particle size. The results show that the initial position of ice crystal melting tends to move to the rear stage of the low-pressure compressor with the increase in ice crystal size, and the decrease in ice crystal size or the increase in ambient temperature leads to the increase in ice crystal melting ratio. On this basis, the hypothesis of spherical ice crystals with equal particle size is broken through, and the influence of sphericity of non-spherical ice crystals and the particle size distribution of spherical ice crystal on the melting characteristics were analyzed by considering ice crystal shape and particle size distribution. The results demonstrate that the sphericity has an effect on the ice crystal melting ratio within a certain range. When the sphericity is between 0.710 and 0.958, the ice crystal melting ratio decreases with the increase in sphericity. Compared with the sphericity, the equivalent diameter of non-spherical ice crystals has a more significant effect on the ice crystal melting ratio. When the mean volume diameter (MVD) of the ice crystal is constant, the difference in particle size distribution leads to the maximum deviation of 20.5% in the ice crystal melting ratio at the same position in the compressor. For the particle size distributions with the same MVD but different coefficients of variation, in the front half of the ice crystal melting characteristic curve, the melting of small-sized ice crystals is dominant, and the particle size distribution with a larger coefficient of variation has a relatively higher melting ratio. However, in the latter part, the melting of large-sized ice crystals is dominant, and the particle size distribution with a smaller coefficient of variation has a relatively higher melting ratio.