The invention provides a cardiopulmonary harmony series index evaluating method, device and system. The method includes the following steps that electrocardio signals, respiratory signals and motion signals of evaluated people are filtered, denoised and pretreated, a RR interval sequence is extracted from the electrocardio signals, and according to the RR interval sequence and the respiratory signals, a binary regression mathematical model is constructed; parameters in the binary regression mathematical model are transformed to a frequency domain to obtain a transformation matrix; the transformation matrix is analyzed to obtain a cardiopulmonary harmony series index; the cardiopulmonary harmony series index includes a cardiopulmonary harmony curve, a cardiopulmonary harmony degree, cardiopulmonary resonance frequency, a cardiopulmonary resonance factor, a cardiopulmonary harmony curve bandwidth and a cardiopulmonary resonance quality factor; and the cardiopulmonary harmony curve is used for representing the effect value of respiration on the modulation of the RR interval sequence at different frequency points in the frequency domain. By proposing the concept of the cardiopulmonaryharmony series index, the embodiment of the invention provides a method to obtain the cardiopulmonary harmony series index, and can provide the reliable digital measurement for the evaluation of a cardiopulmonary metabolism system.