Abstract: The influence of bubbles shape on acoustic behavior plays a crucial role in studying the characteristics and parameter detection of gas-liquid two-phase flow. A Monte Carlo prediction model for ellipsoidal bubbles is developed for a non-spherical bubble system, which combines the Monte Carlo method with the T-matrix method. Based on the model, the attenuation coefficient of the millimeter-sized ellipsoidal bubble cluster at the frequency of 50-500 kHz is calculated in numerical simulation, revealing the variation rules of the attenuation coefficient and the acoustic behaviors with the bubble morphology and size. The results show that, with the elongation of a bubble, the forward amplitude of the scattered sound pressure decreases and the backward amplitude increases; the scattered sound pressure exhibits angular redistribution and directional deformation depending on the incident direction. The anechoic efficiency tends to enhance with bubble elongation, particularly at low dimensionless parameters. The transmission behavior of sound waves in the bubble cluster goes down with the amplification of the major-to-minor axis ratio of the ellipsoid, while the scattering behavior exhibits the opposite trend. The attenuation coefficient climbs with both the elevation of the acoustic wave incidence angle and the major-to-minor axis ratio. Notably, when the major-to-minor axis ratio exceeds 1.1, a measurable change in attenuation coefficient occurs. The attenuation coefficient diminishes with the enlargement of bubbles, and its rate of change becomes less pronounced. For the bubble cluster with a mean radius of 2.5 mm obeying a normal distribution function, the acoustic attenuation coefficient augments as the radius distribution broadens. Specifically, when the standard deviation of this distribution is raised to 0.5 for bubbles with a radius of 2.5 mm, there is a 6.51% increase in the attenuation coefficient.