Objective  To investigate the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the expressions of matrix metalloproteinases-2 and matrix metalloproteinases-9 (MMP2/MMP9) of human dermal fibroblasts and relevant mechanisms.  Methods  ELISA and Gelatin zymography were adopted to detect concentrations and activity of MMP2/MMP9 in the supernatant of fibroblasts treated by GM-CSF of different concentrations (0, 10, 50, 100, 500 ng/mL). The protein levels of MMP2, MMP9, JNK, p-JNK, c-Jun, and p-c-Jun and mRNA levels of MMP2 and MMP9 of fibroblasts treated by GM-CSF or SP600125+GM-CSF were detected by Western blotting and real-time PCR, respectively. The concentrations of MMP2/MMP9 in the supernatant of fibroblasts treated by GM-CSF or SP600125+GM-CSF at different time points (6, 12, 18, and 24 h) were detected by ELISA.  Results  GM-CSF could significantly induce expression and secretion of MMP2/MMP9 of human dermal fibroblasts (P<0.05) and the concentration and activity of secreted MMP2/MMP9 positively correlated with the concentration of GM-CSF. The phosphorylation of JNK and c-Jun and the mRNA level of MMP2/MMP9 of fibroblasts treated by GM-CSF were higher than those of controls (P<0.05). The phosphorylation of c-Jun and the mRNA level of MMP2/MMP9 induced by GM-CSF were significantly inhibited after being pretreated by SP600125 (P<0.05). The expression of MMP2/MMP9 of fibroblasts induced by GM-CSF reached the peak at 24 h and gradually decreased from 24 to 48 h (P<0.05). The expression of MMP2 of fibroblasts treated by both SP600125 and GM-CSF was significantly lower than that of controls, while the expression of MMP9 was slightly higher than that of controls.  Conclusion  GM-CSF can induced the expression and secretion of MMP2/MMP9 of fibroblasts by activating the JNK/c-Jun signaling pathway.