In this study, Arius maculatus were collected using the samples caught by bottom trawling off the southwestern coast of Taiwan. Length-weight and length-length, fork (FL), standard (SL) and total (TL) lengths, relationships were determined. The relationships between the lengths were all significantly linear (p<0.01), the b value in the length-weight relationship for this value was significantly lower than 3 in the fall (p<0.01), when the temporal changes were taken into account, indicating that only the sampling time affected the growth pattern of A. maculatus. The growth was isometric in the spring, summer and winter, but it was negative and allometric in the fall.