Infrared physiotherapy is a new method with the application of infrared light to human body parts, whose effect has been widely reported in the treatment of various diseases. Nowadays, the effectiveness of the infrared physiotherapy was generally assessed by the experience of the medical staff qualitatively. As the parameters of blood flow is the key of physiotherapy evaluation, using a noninvasive, safe, and real time monitoring way on blood flow during therapy will benefit guiding the physiotherapy arrangement to enhance the therapy effect. This paper proposes a method based on bioimpedance technology for infrared physiotherapy evaluation in human arm. Firstly, we choose the BIOPAC physiological information recorder as the core of measure system, with double-probe method to measure ECG signal, and four-probe way to synchronously measure the bioimpedance change of human arm before, during and after the infrared irradiation. Then removing baseline drift and extracting feature points by using wavelet transform, applying simple Bayesian model to ensure the stability of the feature points. The experimental results show that (1) The arm bioimpedance signal characteristic frequency matches the heart rate with an average difference 0.09%-1.60%. (2) After the infrared irradiation, the ratio between secondary and the main wave peaks of arm bioimpedance rises 3.91%-13.05%, namely, bioimpedance can represent the change in arm blood flow, and sensitive enough to make an evaluation of infrared physiotherapy.