Abstract: The mechanical properties of pile foundations in coral sand ground have emerged as a major focus in reef island engineering in recent years. Given the mechanical characteristics of coral sand, such as its tendency to fracture and its rough surfaces, acoustic emission signals are easily generated under stress. This study explores the characteristics and evolution of acoustic emission parameters during the pile penetration process in coral sand through a series of model pile penetration tests. The results reveal a strong correlation between acoustic emission parameters and model pile loading, with both exhibiting similar variation patterns with penetration depth and displaying distinct three-stage evolution characteristics. The effect of density on acoustic emission is more complex; a denser coral sand foundation does not necessarily produce stronger acoustic emission signals. When the cumulative penetration depth reaches 40 mm, the acoustic emission parameter values for foundations with different densities are generally similar. Under cyclic loading, acoustic emission events remain inactive and exhibit a certain Kaiser effect at low loads(initial loading stage). Overall, aside from the notable differences in the average amplitude of acoustic emission events during the initial loading stage, other parameters(such as event count, ring-down count, and energy) show similar variation patterns.