Laser speckle contrast imaging (LSCI) technique is a new modality to monitoring blood flow dynamics with high spatio-temporal resolution. It records the full-field spatio-temporal characteristics of microcirculation without the need of scanning in real time. In this study, an in vivo model of chick chorioallantoic membrane (CAM) at embryo age (EA) of 10 days, was observed following photodynamic therapy (PDT) irradiated by semiconductor laser (λ=656.5 nm) whose light intensity incident on the treatment site was maintained 40 mW/cm2 using the photosensitizer of pyropheophorbide acid (Pyro-acid). The changes of vessel structure and blood flow velocity were recorded respectively. This study shows that LSCI can assess the efficacy of peripheral vessel damage of tumor in PDT by monitoring changes of vessels structure and blood flow velocity.