An arrhythmia detection method, an arrhythmia detection device and an arrhythmia detection system are provided. The arrhythmia detection device comprises a processor to: equally divide an electrocardiogram signal through each time interval to acquire respective sequences of electrocardiogram signal segments； determine an arrhythmia probability for each electrocardiogram signal segment in each of the sequences of electrocardiogram signal segments； and for each two adjacent time intervals, determine an arrhythmia detection result for each electrocardiogram signal segment in the sequence of electrocardiogram signal segments corresponding to a shorter one of the time intervals in accordance with the arrhythmia probability for each electrocardiogram signal segment in the sequence of electrocardiogram signal segments corresponding to the shorter one of the time intervals, and the arrhythmia probability or an arrhythmia detection result for each electrocardiogram signal segment in the sequence of electrocardiogram signal segments corresponding to a longer one of the time intervals.
