Abstract: Effects of water temperature(8,18 and 28℃)and salinity of 10,20,and 30 on Shewanella loihica ECSMB14101 biofilms and subsequent effect on settlement of plantigrades of mussel Mytilus coruscus with shell length of(1.81±0.13)mm were studied.The confocal laser scanning microscopy technique was used to investigate the characteristics of biofilms including biofilm thickness and the distribution of bacteria in biofilms.The results showed that the final density and thickness of the ECSMB14101 biofilm were increased with increase in temperature and salinity,with the maximal thickness of(4.4±0.1)μm at a salinity of 30 and at temperature of 28℃. The settlement inducing activities of the biofilms were different under different conditions of temperatures and salinities.The amount of bacteria in the biofilm was found to be increased with the increasing temperature,and the mussel had settlement rate of 31%at 8℃and 68%at 18℃,with significant difference(P<0.05).In contrast, there was no significant difference in inducing activity at 18℃and 28℃(P>0.05).The findings explored the interplay between environmental factors,biofilm formation,and settlement of mussel plantigrades.