Objective To assess the expression level of D-Tyr-tRNATyr deacylase (DTD) in SAMP8 mice and speculate the function of DTD in disorders associated with Alzheimer's disease (AD). Methods Altogether 12 SAMP8 mice and 12 SAMR1 mice were used in this study. Semi-quantita- tive reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were performed to detect the mRNA and protein levels of DTD in the mice. Purified DTD protein was injected into lateral ventricle to investigate the function of DTD in SAMP mice. The behavior of the mice was tested by using a Step-through Test System. Results Both mRNA and protein levels of DTD were found to be significantly lower in SAMP8 mice compared with those in SAMR1 mice (P<0.05). In vivo injection of DTD protein did not lead to an obvious change in behavior of SAM mice. Conclusions DTD might function in the process of AD-associated pathology and could possibly participate in physiology process in a long-term manner to orchestrate with other regulators in order to maintain the balance of organism.