Acetaldehyde is an intermediate of alcohol metabolism,but its effect on alcohol dependence is not clear. It was performed with conditioned place preference(CPP)and conditioned taste preference(CTP) experiments to investigate the effects of acetaldehyde on the alcohol dependence in mice. The mice showed significant CPP to ethanol (n = 6,P 0.01)while training with ethanol for 8 times after pre-treatment with 0.8% ethanol for 7 days,but no significant CPP effect on acetaldehyde was observed (n = 6,P 0.05). While trained with 0.8% ethanol and with 0.4% acetaldehyde, the CPP effect to ethanol decreased (n=6, P 0.01). Mice also showed the CTP to ethanol after drinking water and 10% ethanol for 7 days (n = 6, P 0.01),but the CTP to ethanol decreased while 1% acetaldehyde was added in drinking water. Mice showed no CTP to ethanol after treated with 1% acetaldehyde for 7 days,but the drinking to the admixture of ethanol and acetaldehyde increased. The results showed that acetaldehyde had important roles in alcohol dependence behavior in mice.