In this study, cultured monolayer normal human skin fibroblasts (HSFs) were irradiated with the fundamental (1064 nm) and the second harmonics (532 nm) waves of Q-switched Nd∶YAG laser beams, to study the photobiomodulation of marginal irradiation of high intensity laser beam. For each laser beam, the power output ranged from 0.2～1 W in pulsed mode, and the irradiation time was fixed at 20 s. Cell proliferation was performed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay immediately after laser treatment 24 hours and 48 hours, respectively. It was found that high pulse energy irradiation results in small survival rate and large damage radius, and HSFs proliferation was significantly promoted after 24 hours/48 hours 1064 nm laser treatment with 100 mJ and 150 mJ pulse energy, but significantly inhibited after 24 hours/48 hours 532 nm laser treatment with 100 mJ pulse energy. These results indicate that there is the photobiomodulation for marginal irradiation of high intensity laser beam, which might play an important role in the long term effects of laser surgery.