Abstract: The “scalelike projects” on the derma of 3 species of Hippocampi, H.kuda Bleerer, H.trimaculatus Leach and H.japonicus Kaup were observed by scanning electron microscope (SEM). Results showed that some characteristics such us size, shape and type of arrangment of the “scale-like projects” can be considered as the evidence for microanalysis. Image quantiative analysis of the “scale-like project” was carried out on 45 pieces of photograph using area, long diameter, short diameter and shape factor as parameters. No difference among the different parts of the same species was observed, but significant differences were found among the above 3 species.