Objective To observe the effect of acupuncture at Hehu（LI 4） and lateral non-acupoint on the transcutaneous oxygen partial pressure（tcPaO2） and transcutaneous carbon dioxide partial pressure（tcPaCO2） of distal acupoint Quchi（LI 11） in order to provide evidence for the propagated sensation along channel（PSC）.Methods The laser Doppler flowmeter was adopted to measure the level of tcPaO2 and tcPaCO2 of 20 healthy volunteers for 3 times.First

acupuncture at the right side non-acupoint for observing the lpsilateral acupoint（non-Hehu-Quchi group）;Second

acupuncture at the contralateral acupoint for observing the lpsilateral acupoint（Hehu-Quchi group）;Third

acupuncture at the right side acupoint for observing the lpsilateral non-acupoint（Hehu-non-Quchi group）.The changes of tcPaO2 and tcPaCO2 before treatment and 1 minute

5 minutes

and 10 minutes after acupuncture in each group were recorded and compared.Results Before acupuncture and 1 minute after acupuncture

the values of tcPaO2 and tcPaCO2 of all groups were without statistical difference（P>0.05）.Five minutes after acupuncture

the values of tcPaO2 and tcPaCO2 of Hehu-Quchi group and Hehu-non-Quchi group were significantly higher than before acupuncture and that of non-Hehu-Quchi group at the same time point（P<0.01 or P<0.05）. Ten minutes after acupuncture

the value of tcPaO2 of Hehu-Quchi group was significantly higher than before acupuncture and that of non-Hehu-Quchi group at the same time point（P<0.01）.The value of tcPaO2 of Hehu-non-Quchi group was decreasing and lower than five minutes after acupuncture（P<0.05）

but it was still higher than before acupuncture and that of non-Hehu-Quchi group（P<0.01）.Compared with before acupuncture

five minutes after acupuncture

and the Hehu-non-Quchi group at the same time point

the value of tcPaCO2 of Hehu-Quchi group was higher

and the difference was statistically significant（P<0.05 or P<0.01）.The value of tcPaCO2 of Hehu-non-Quchi group was higher than that of five minutes after acupuncture（P<0.01）.There was no statistical difference before and after acupuncture in the non-Hehu-Quchi group（P>0.05）.Conclusion Acupuncture at Hehu（LI 4） is able to continuously increase the tcPaO2 and tcPaCO2 of distal acupoint and lateral non-acupoint

while acupuncture at non-acupoint is not able to influence the tcPaO2 and tcPaCO2 of distal acupoint and non-acupoint

which indicates the propagated sensation along channel.