Considering the coral reef rock mining difficulty in dredging project,the paper analyzes the coral reef rock mechanics index based on large amounts of geotechnical test data.The results show that:1)Due to its water-softening characteristics of dredge coral rock,a reasonable stage excavation procedure should adopts；2)The relativity of moisture content with saturated uniaxial compressive and tensile strength,and with modulus of deformation are strong which all the three regression coefficients of empirical formula are above 0.691；3)Water has important influence on the mechanical properties of coral reef rock,mainly about physical weakening effect and mechanical effect.