Abstract: Experimentalcadmium (Cd) poisoningwasconductedon 200 grasscarpwithweightof 10.8g ?1. 2g. The content of Cd in the water of each experimental group was 80μg?L -1 for 1/ 10 LC50 group , 16μg?L -1for 1/ 50 LC50 group ,8μg?L -1 for 1/ 100 LC50 group , the control group < 1μg?L -1. This experiment lasted 120 days. The results indicated (1) the 24h LC50 in grass carp was 800μg Cd?kg -1weight. (2)themortalityratesin 1/10 LC50 group, 1/50 LC50 group, 1/100 LC50 group and controlgroup were: 64 %, 24 %, 20 %, 4%. (3) the contents (wet) of Cd in hepatopancreas , kidney , vertebra in experimental groups were very significantly higher than those of control group ( P <0.01). (4) the contents of glucose (GLU ), cholesterol (CHOL )glutamic2 oxalacetic2transaminase (GOT ) , alkalinephosphatease (ALP ) in blood plasma in experimental groups were significantly higher than those of control group ( P < 0 . 05 ) , but total protein ( TP ) is lower significantly ( P <0.05). (5) the contents (wet ) of Ca in vertebra and Ca, P, Mg in serum in experimental groups were significantly lower than those of control group ( P < 0. 05) . (6) The pathology showed that hepatocytes , nenal tubule and globule epithelial cells were granular degeneration , hydropic degeneration and fatty degeneration , dissolved necrosis , cyrtosis , silks of gill sinked , osteodysplasty. Ultrastructural changes showed that mitochondria in hepatocytes and kidney epithelial cells were swollen with disintegration and lysis of cristaes , endoplasmic reticulum was hyperplastic and fragemented. The thickness of basal membrane of the kidney glomerulus was found.