To explore the protective and repairing effect of Gukang serum for the F-actin of osteoblasts. Methods: Two groups of New Zealand adult rabbits were fed with Chinese medicine Gukang Fang and estradiol valerate to make the serum containing Gukang and estrogen. The osteoblasts were separated from SD rats and then cultured. The cells were seeded onto cover glasses, and divided into Chinese medicine group and estrogen group, which were cultured with Gukang-containing serum and estrogen-containing serum respectively. Non-drug group(control group) and blank group were also set up. The Chinese medicine group, estrogen group and control group were centrifuged at 240 g and 200 g for 4 min. All the samples were fixed by paraformaldehyde solution and then dyed by FITC-phalloidin. The samples were observed by confocal microscope, and the fluorescence intensities were calculated and compared by one-way ANOVA. Results: The two groups disposed by drug-containing serum showed better fluorescence intensitiy than the control group(P<0.001). At 200 g, Chinese mecicine group presented better than the estrogen group in fluorescence intensity; while at 240 g, estrogen group performed better in fluorescence intensity, and the differences were significant(P<0.001). Conclusion: Gukang-containing serum may protect and repair the microfilaments in osteoblasts of rat when exposed to centrifugal force, yet as the force increases, the protective and repairing effect might be limited.