Abstract： Objective To detect the expression of type Ⅰ collagen, type Ⅲ collagen, prolyl-4-hydroxylases (PH4) and matrix metalloproteinase 1 (MMP-1) in sacral ligament fibroblasts under stress, to understand the collagen synthesis and metabolism in stress situations change. Methods Eight patients who underwent abdominal hysterectomy for uterine benign disease were enrolled in this study. Primary sacral ligament fibroblasts were isolated by explant. After mechanical loading, gene expression of type Ⅰ , Ⅲ collagen, PH4 and MMP-1 were measured. Results Stress of 8% continuing for 24 hours, collagen Ⅰ (1. 13 ± 0.24), collagen Ⅲ (1.05 ± 0. 31) mRNA expression and PH4 expression (1.11 ± 0. 31) compared with static groups (1) showed increasing trends;when the stress were 4% and 12%, collagen Ⅰ (0. 86 ± 0. 26 and 0. 85 ± 0. 25), collagen Ⅲ showed increasing trends (0. 74 ± 0. 29 and 0. 83 ± 0. 38) mRNA expression were decreased. After removal of the stress, in the stress of 4% for 1 hour, collagen Ⅰ (0.79±0.40, 0.97±0.24 and 1.46 ±0.75), collagen Ⅲ (0.86±0.40, 0.99±0.60 and 1.59±0.82) and PH4 (1.11 ±0. 51, 1.17 ±0. 54 and 1.37 ±0. 39) mRNA expression increased gradually. In 8% stress group, collagen Ⅰ mRNA expression (1.16 ± 0. 62, 1.01 ± 0. 51 and 1.05 ± 0. 80) reached the peak in day 1, and collagen Ⅲ (0.99 ±0.69, 1.59 ±0.55 and 1.03 ±0.91) and PH4 (1.05 ±0.31, 1.07 ±0. 80 and 0. 85 ±0. 31) mRNA expression reached the peak in day 2, then decreased. 4% and 8% of the stress with time after the change, MMP-1 mRNA expression have peaked at day 1. Conclusions Moderate stress could contribute to pelvic floor collagen synthesis, too much or too little stress is not conducive to the synthesis of collagen. Collagen Ⅰ and collagen Ⅲ on the stress response may be different, the former have faster reaction than the latter. PH4 were involved in the synthesis of collagen, while MMP-1 may play a role in collagen degradation.