Abstract: This study aimed to examine the feasibility of using Grandidierella japonica cultured in laboratory at 20℃ constant temperature as test organisms for assessing toxicity of marine sediment.In 10-day sediment acute toxicity tests,the variation of mortality of G.japonica in contaminants sediments from Jinzhou Bay was determined.The result showed that there was no significantly difference of mortality amongst G.japonica from f₁、f₂、f₃、f₄ generation in the great mass of locations(except location 1 and 2).There was no significantly difference of mortality between G.japonica from field collected and lab cultured in the great mass of locations(except location 1 and 2).Depending on the results of sediment acute toxicity test,the transaction investigated in Jinzhou Bay may be divided into three sections to assess the sediment quality: heavily polluted area(location 1 and 2);polluted area(location 3 and 4);relativity natural area(location 5 and 6).The variance trend of the sediment toxicities to G.japonica was coincident with the distribution trend of the contaminants in the sediment.G.japonica cultured in laboratory was ideal testing organism for sediment toxicity test.