Objective：To examine expressions of embryo gene Tbx18 in adult mice after experimental myocardial infarction（MI）and to study the spatiotemporal characteristics of embryo gene Tbx18 from adult mice with injured myocardium. Methods：Totally 90 C57BL/6 mice were divided into sham group and MI group randomly. MI model of adult mice was induced by ligating the left anterior de－scending coronary artery on right lateral position. Real-time fluorescence quantitative PCR and Western blot were respectively used to measure the mRNA and protein expressions of Tbx18 in infraction and adjacent area of MI group on 1，3，5，7 d after operation，and comparison was made between MI group and sham group. Results：PCR results indicated a remarkable increase of Tbx18 mRNA in infraction and its adjacent tissues of MI group on 3，5 d after operation compared with those in sham group（F=2 778.88，P=0.000；F=462.36，P=0.000）. Results of Western blot showed that expressions of Tbx18 protein in mice infraction tissues reached the peak on 3，5 d after operation（compared those on 1 d after operation，t=7.982，P=0.000；t=9.307，P=0.000），which was consistent with PCR re－sults. Immunofluorescence results on 3，5 d after operation revealed that the expression area mainly located at infraction and its adja－cent area. Conclusions：A transient activation of embryo gene Tbx18 exists at infraction and its peripheral area in the adult mice with MI，especially on 3，5 d after operation.