is one of the actin family, especially in maintaining cell structure, movement and physical activity in cell division and playing an important role in quantitative genetic experiments. In this study, homology cloning and RACE techniques were used to amplify Siberian sturgeon ( gene cDNA full-length. Sequence analysis showed that the full-length of gene cDNA had 1322 bp, which consisted of a 1128 bp open reading frame (ORF) encoding 375 amino acids, a 137 bp 5untranslated region (5UTR) and a 57 bp 3untranslated region (3UTR). Multiple alignment analyses showed Siberian sturgeon was much closest to other fishes. Meanwhile, homology cloning method was used to obtain the Siberian sturgeon’s gene homology Sequence, which had 768 bp and shared over 70% similarity with other species. And then gene was used as a internal reference on detecting the expression of gene in various tissues and various embryonic development periods of Siberian sturgeon by real-time fluorescence quantitative PCR. The results showed 2 were relatively low in liverkidney and brain. However, in muscle tissue, the expression level of gene had expressed in various periods of the Siberian sturgeon embryo, the relative expression level of gene was low in the fertilized egg period and blastocyst. In the gastrula, neurula period, formation of visual bubble and formation of heart, the expression of gene reached to relatively high. At the same times, in the formation of heart, the expression of gene reached to the highest. This research will provide a solid tool to quantify the expression of the related genes during the development of Siberian sturgeon embryo and lay a foundation for the further study on the role of