Abstract: In present study，body length was measured in 15 individuals of fat greenling Hexagrammos otakii by an underwater photogrammetry system，in which a 3 d photogrammetric system was reconstructed via the calibration of distortion of the camera itself and the complex refraction of light in underwater environment，and compared with the body length measured manually to evaluate the feasibility of the fish length measurement using the underwater photogrammetry system.The results showed that the correlation coefficient of 0.933 was found between the values of body length measured by the underwater photogrammetry system and the body length measured manually，with significant difference of 0.003，relative error of 2.1%－18.1%，and absolute error of 2.9－33.0 mm.Manual measurement the measurement of fish body.There was error in body length measured by the underwater phogogrammetry system compared with the fish body length measured manually，which is primarily derived from the difficulty in fish control points extraction，and the certain error in manual measurement.The findings indicate that the underwater photogrammetry system can be used in measurement of fish body length even though it has some errors.
2018, Vol. 33 
