Abstract: Spanish mackerel Scomberomorus niphonius is one of the maincommercial fishes in the China sea. Based on the biological date of 8627 sa-mples which collected from commercial catches in the Yellow Sea, Bohai Sea andnorthern East Sea during June to March (next year) in 1963--1991, this paperdiscribed the characteristics of growth of spanish mackerel underyearing as fol-lows: 1. The relationship between body length (L) and body weight (W) is W =8.7231×10^-8L.⁰⁸³⁸ (r = 0.9994). The parameter branges within 2.9868--3.0355 indifferent year 2. The general pattern of the growth is expressed by von Bertalanffy growthequation as; L_1 = 422. 841-e^{(-0.18838)(t-2.18)}; W_t = 629. 661-e^{-0.1388)(t-2.18)8}. The grow-th inflection for body weight is in 10.11 (a period of 10 days) and the growth israpid before November 1 for body length and during August 1 to November 1 forbody weight. 3. There are fluctuations of the growth for the different year. The growthdiffers to 1963--1979 since the autumn population of spanish mackerel underyear- ing has be exploited by trawl fishery after the end of 1970s and the parameters ofgrowth change as: L_1∞) from 438.00mm to 399 .06mm,W_∞ from 6/5.82g to 512.16g,k from 0.1336 to 0.2307, the growth inflection for body weight from 10.61 to 8.74(a period of 10 days) and the main growth stage for body weight from 7--16 to 6-13 (a period of 10 days) (i. e. from August 11-November 11 to August 11-October11). 4. It is consideration to the characteristics of growth of spanish mackerelOctober 21 for achievement to the rational utilization of its resource.