It has been reported that pulsations in abnormal vessels are observed on indocyanine green (ICG) angiography in half of patients with polypoidal choroidal vasculopathy (PCV), although the mechanism of the pulsation is unknown. In this study, we report a case of PCV showing venous pulsations at an arterio-venous (A-V) crossing, and discuss a possible mechanism of polypoidal vessel formation and pulsations in PCV. A 66-year-old female presented with a reddish-orange elevated lesion and serous retinal detachment in the macula of her left eye, and was diagnosed as PCV. She was treated with photodynamic therapy (PDT), and followed-up through routine examinations, including ICG angiography. ICG angiography at presentation showed a branching vascular network and choroidal venules with dye leakage (polypoidal vessels) in the left eye. Pulsations, supposedly of venous origin, were observed at an A-V crossing in the abnormal vessels. Within 3 months after PDT, the polypoidal vessel ceased to leak and the pulsations vanished. The reddish-orange lesion gradually decreased in size with complete disappearance of retinal detachment. This study suggests that an unusual compression at an A-V crossing may make a venule polypoidal, and fluctuations of blood flow and pressure in the venule may cause pulsatile movements of the vessel wall.