Abstract: Soletellina diphos is a rare and endangered economic shellfish only distributed in the southwest intertidal zone of Nanri Island which possesses less human interference and environmental pollution in Putian sea area,Fujian Province.In order to discern the germplasm and genetic background of this indigenous population,shell length,shell height,shell width and body weight of 1 year old cultured and 2~3 years old wild S.diphos populations were observed and measured morphologically by using of vernier caliper and precision scales to derive the calculation formula between these quantitative characters.12S rRNA,16S rRNA,COI,Cytb,H3,18S rRNA,ITS as well as 28S rRNA of wild individuals were amplificated and sequenced respectively through the method of conventional PCR and clone.Neighbor-Joining phylogenetic trees involved in those related homologous sequences of Psammobiidae or Tellinoidea were reconstructed based on the comparison and analysis of sequence similarities and genetic distances.The enzymatic activities,specificity and polymorphism in relation to two different tissues of six isozymes including EST,IDH,LDH,MDH,ME and SOD extracted from the adductor muscle and axe-shaped foot muscle were determined and analyzed with vertical slab polyacrylamide gel electrophoresis and isoenzyme specific dye.The results showed that correlativities between shell length and height,shell length and weight,shell height and weight were high,and the mean ratios of shell length to height were(2.06±0.08) times and(2.07±0.08) times,similar in both of the cultivated and feral populations.The growth equations between shell length and shell height,shell length and body weight,shell height and body weight could be successively described by the linear function H=0.478 7L+0.042 5(R²=0.983 1),power function W=0.059 1H^{3.045 9}(R²=0.990 2) and W=0.529 5H^{3.058 2}(R²=0.993 2),respectively.Different geographical specimens of S.diphos revealed certain hereditary variation in 12S rRNA,16S rRNA,COI and Cytb base compositions,genetic distances and molecular evolutionary trees.Meanwhile,S.diphos and S.adamsii may belong to the potential synonyms or geographic subspecies according to 16S rRNA and 28S rRNA experimental results.Besides SOD,distinct tissue expression specificity of EST,IDH,LDH,MDH and ME were examined.LDH was not found expressing in axe-shaped foot muscle tissues among all the six isozymes while ME was detected with strong enzyme activity in adductor muscle.EST exhibited clear enzyme spectrum and had apparent polymorphism in the number of enzyme bands between individuals.The study will provide a valuable reference for further research in identification,genetic structure and variability of local natural S.diphos resources.