In order to study the biological parameters and reproduction characteristic of Leptodius exaratus in intertidal zone of Hormoz Island, a series of research sampling carried out during 12 months in 2013. The sex ratio was estimated as male: female=47%:53%. Reproduction of the dominant species showed higher abundance of males than females. Sexual maturity in male occurred at 16 mm carapace length and in female at 13mm carapace length. Gonopod length in male crab is strongly correlated with the maturity and so is the number of eggs and gonad weight with the width of the abdomen in females.