Gonadal origin and gonadal different iation of cultured Chinese sturgeon, Acipenser sinensis were studied using light microscope. The primordial germ cell( PGC) was first seen below the nephridium area on the third day after hatching, and by the 11th day the primordial gonad, genital fo ld formed. Later, with the gonad growing, the blood vessel appeared in it when f ish was 2 months old and the adipose fatty tissue appeared by the age of 7 months. According to Hochleithner &Gessner( 1999) , we classif ied stage 0 of gonad development of this f ish as the stage with no histological sex differentiation. Histological sex differentiation of the gonads was completed by the age of 9 months( 0. 6 - 1. 1kg B. W. ) , and the gonads entered stage . , during which mitosis of the spermatogonia and oogonia occurred. With the primary spermatocytes or oocytes appearing , the testes or ovaries reached stage ? when f ish were 1. 8- 2. 2 years old( 1. 55- 5. 6kg B. W. ) or 2. 5- 3 years old( 3. 1- 8. 2 kg B. W. ) respectively. After the age of 3 years, the gonads, in succession, became what could be sexed by gross examination, and at the age of 5- 5. 6 years( 18- 35. 5kg B. W. ) , all of the gonads could be sexed by gross examination and st ill remained in stage ? , with the diameter of oocytes of 60- 240Lm.