Abstract: From January 2015 to May 2015, the fish Decapterus maruadsi were collected from the continental shelf of Northern South China Sea. Sagittal otolith length, width, perimeter, area, length-width ratio, circularity, rectangularity, form factor and other basic morphological parameters were measured for the morphological characteristics of the otoliths, models of typical parameters of otoliths’ shape with body length and body weight were built respectively. The results showed that the sagittal otoliths of D. maruadsi in this survey was of long shuttle forms, had rostrum, antirostrum and excisural notch with obvious leafed aragonite crystal and knob, and the central notch was deep and clear. According to the main component analysis, seven main morphology characteristics were described for otolith length, otolith width, perimeter, area, the maximum radius of the otolish, the minimum radius of the otolish, area of the minimum circumscribed rectangle. Models of typical parameters of otoliths' shape with body length and body weight were fitted with both log function. The parameters increased steadily following the body length, but for the body weight, the parameters increased fast at first, and then increased steadily. The area of minimum circumscribed rectangle increased on the fastest speed, however, the maximum radius of the otolish increased on the slowest speed. The changes of circularity, rectangularity and form factor were not obvious and, either, the shape.