1.5-year-old of the pearl oysters, Pteria penguin, were used to produced free marine pearl. 20-months later, 43 good quality pearls were harvested and analyzed. These pearls can be grouped into 3 clusters based on several characters of pearls, including pearl diameter, nacrine thickness, pearl weight and color distance from standard golden pearl. For pearls of group one and group two, it was similar each other in either of L value, b value and color distance from standard white pearl, which were obvious different with group three. Besides, a value was the same for pearls of group one and group 3, and it was obvious different with group two. Relevance analysis results showed that there were distinct relationships between L value of pearl color and pearl diameter, pearl nacrine thickness, or pearl weight, with a correlation coefficient of -0.567、-0.617, and -0.523 respectively. There was no obvious correlation between either of a value or b value and pearl diameter, pearl nacrine thickness, or pearl weight. Moreover, there were also distinct positive correlationships between pearl diameter, pearl nacrine thickness, or pearl weight and color distances from standard white or golden pearls.