Objective To investigate the effects of different vibration durations on expression level of osteogenesis-related proteins by loading low intensity mechanical vibration in the ovariectomized (OVX) rats. Methods Twenty-four 6-month old female Wistar rats were ovariectomized and then randomly divided into 8-week-control group (C8), 12-week-control group (C12), 8-week-vibration group (V8), and 12-week-vibration group (V12). Vibration treatment was started one week after all the rats were ovariectomized. Rats in both V8 and V12 groups were loaded with 35 Hz, 0.25 g low intensity mechanical vibration for 15 minutes per day. C8 and C12 groups served as control without any treatment. Rats were executed in batch at 8th and 12th week, respectively, to analyze expression level of osteogenesis-related proteins, including BMP-2, p-ERK, Runx2 and OCN. Results Low-intensity mechanical vibration enhanced the osteogenesis related protein expression in OVX rats (P<0.01). With the extension of vibration duration, the osteogenesis related proteins BMP-2、p-ERK、Runx2 and OCN in V12 group were increased by 22.61% (P<0.05), 27.96% (P<0.01), 25.85% (P<0.01), 27.05% (P<0.01), respectively, as compared with V8 group. But for the control groups, no significant differences were found in expression level of osteogenesis-related proteins. Conclusions The low intensity mechanical vibration could elevate expression level of osteogenesis-related proteins, and the osteogenesis was enhanced with the extension of vibration duration.