Objective To determine the protective effect of bacterial lipoprotein (BLP) tolerance on myocardiocytes in aged mice, and compare its effect on cardiac function between aged and adult mice. Methods A total of 86 healthy male aged C57BL/6 mice (SPF grade, 24 months old) and another 55 healthy male adult C57BL/6 mice (SPF grade, 6 to 8 weeks old) were employed in this study. Low-dose BLP was used to pretreat the aged and adult mice to induce BLP tolerance. Then the mice were respectively divided into control, sham operation group (sham), sepsis group (CLP, inflicted by cecal ligation and puncture) and BLP tolerance＋CLP group. Echocardiography was carried out in adult mice in 0, 2, 6 and 12h after CLP to measure left ventricle shortening fraction (FS), ejection fraction (EF), left ventricular internal diameter at end-diastole (LVIDd) in adult mice, and in aged mice at time points of 0, 3, 6 and 12h for above-mentioned indices. Results The FS, EF and LVIDd showed a downward trend after operation in the sepsis group and BLP tolerance＋CLP group in aged mice, with the stronger decreases in the former than in the latter group. In the time from 0 to 6h, the BLP tolerance＋CLP group in adult mice had similar tendencies in the FS, EF and LVIDd with sepsis group, but lower than the later. Then the 3 indices were increased in the BLP tolerance＋CLP group in 6h after CLP, and became higher than those of sepsis group in 12h, with FS and EF having significant differences (P＜0.05). The FS in the BLP tolerance＋CLP aged mice presented a progressive decline tendency, but it was in a progressive increase trend after 6 h in adult mice, and was significantly higher than those of the sham and CLP groups at 12h (P＜0.05). The EF of CLP group in adult mice increased after operation, then decreased from 6h and became lower than the preoperative level at 12h. While the EF of CLP group in aged mice showed a progressive decline tendency after surgery. The EF of BLP tolerance＋CLP group in adult mice was in a progressive increase trend; on the contrary, the corresponding group in aged mice was tending downwards. The LVIDd of the BLP tolerance＋CLP group in aged mice was progressively reduced, while that of corresponding group in adult mice was below the preoperative level in 2h after operation (P＜0.05), then gradually recovered in 6h. Conclusion Sepsis has inhibitory effects on FS, EF and LVIDd, and the effects on cardiac systolic and diastolic functions are stronger in aged mice. BLP tolerance exerts protective effect on cardiac function. This protection is apparently effective in adult mice than in aged mice.