Abstract: Yolk is the primary nutrition material during the development of embryo, of which vitellin is primary constitute element.In order to know the biochemical character sand synthesis path way of yolk protein from Acipenser ruth enus, the Yolk protein was abstracted.The biochemical character and synthesis path way of yolk protein from Acipenser ruth enus were Studied by chromate graphy with SephadexG2200, polyacry lamidegel electrophoresis, western-blottin gand immunohisto-chemistry.The results showed that yolk protein was composed of lipovitellin, yolk immunoglobulin and Phos-vitin. Lipovitellin was a kind of glycosyl, phosph or usand lipid protein and it was same as female serum specific protein (FSSP).Ithad females pecificity and it santi body had genusand tissuespecificity.Themo lecularweigh to fLipovitellin was144kD, which was composed of two subunits with molecular weight of 97.4kD and 30kD, respectively, itsisoelectric pointwas7.50.Phosvitin was made up of two subunits with molecular weight of 47.6kD and 16.8kD, respectively, itsmo-lecular weigh was 66kD and is oelectric point was 8.65. The rabbit anti serums of Lipovitell in were prepared, and immune histo chemistry location was investigated inliver, in-testine, egg(Ⅱ-Ⅴ periodovary) and bloods mearsat differentage.The results showed that livercell so ffemalesturgeon atⅣ stageovary and aboveⅣ stageovary were immunostained with DAB, which indicated the liver cells were positive to special antibody and positive reaction occurred mainly in the cytoplas mofliver cells.Nospecial immunostaining was ob-served either in liver cells of males turgeon and females turgeon which ovary was duringⅠ-Ⅲ period or incontrol group.The surface of blood cells of female sturgeon which gonad was atⅣ-Ⅴ stage was positive to special antibody.In contrast, the surface of blood cells of mature male sturgeon, female sturgeon duringⅠ-Ⅳ period ovary and negative con-troll were negative to special antibody.The intestine cells of anteriorintestine, midintestine and posteri or intestine before maturing in both male and female sturgeon were also negative to special antibody.There were a lot of positive reaction sub-stance sinnucleus duringⅡ period ovary.Grand growth phase3 primary oocyteoccupied the greaterpart of Ⅲ stageovary which couldbed ivided intononage, meta phase and anaphasestage.A lot of positive reaction substance sexisted innucleus atnonagestage ofⅢ stage ovary.When the ovary developed tometa phase, positive reaction substances of nucleus began to decrease, whereas, it appeared incytoplasm.The cells were ovaland the positive reaction substance sincreased atana phase stage.There were no positive reaction substance satⅣ stage ovary butyolkgranu leap peared positive reaction.A lot of yolk granule which were positive inoocyte appeared inⅤstage ovary. Inconclusion, the synthesis style of yolk protein from Acipenserru the nusLinnaeus was belonged to facultative.Before Ⅳ stageof ovary, the yolk protein was mainly synthesized by oocyteoneself, which was auto synthesis. When ovary devel-opedtoⅣ stage, oocytesstoped to synthesize yolk protein and livercells began to synthesize vitello genin which was trans-ported to ovary by blood circulation.After endocytosis by developing oocytes, vitellogenin was enzymatically converted into egg yolk protein, which was endogenesis.