Objectives : The second derivative of photoplethysmogram waveform(SDPTG) is a simple, convenient and non-invasive technique for pulse wave analysis. This study was designed to investigate the differences in the SDPTG between the affected side and the unaffected side in hemiparetic patients after stroke, and the effects of acupuncture at Palsa(BaXie) in hemiparetic patients after stroke. Methods : To evaluate the differences between the affected side and the unaffected side in hemiparetic patients after stroke, their SDPTG were recorded by using a Cardio Peri SA6000. To evaluate the effects of acupuncture at Palsa(BaXie) in 20 hemiparetic patients after stroke and 20 healthy subjects, their SDPTG were recorded 2 times(pre-acupuncture and post-acupuncture). The SDPTG consists of an a, b, c and d wave in systole and an e wave in diastole. Sano aging index was defined as (b-c-d)/a. Results : 1. The affected side in hemiparetic patients after stroke had higher average b/a ratio(p<0.05)and Sano aging index(p<0.05) than the unaffected side 2. In a comparison of pre-acupuncture and post-acupuncture at the Palsa(BaXie), b/a ratio(p<0.05) and Sano aging index(p<0.05) was decreased significantly in both hemiparetic patients and healthy subjects. Conclusions : These findings suggest that acupuncture at Palsa(BaXie) may be effective method of reverting some of the deleterious effects on vascular function produced by stroke.