To discuss the progress and relevant issues in biomarker research on blood flow signals at acupoints. Acupoints can not only be used to treat diseases, but also reflect the functional state of viscera under certain conditions. In diseases, the functional state of some acupoints changes, accompanied by changes in microcirculation. Our study shows that coherence analysis between blood flow signals can be used not only to distinguish different age groups, but also to distinguish different cold stimulation of the digestive tract. Therefore, blood flow signals at acupoints can be used as a potential biomarker for evaluating the functional state of the body.