The invention discloses a step calculation method. The step calculation method comprises following steps: after acquisition of three axises acceleration of arms and hands swinging by a pedometer, reference acceleration of the three axises acceleration in a preset acquisition time is subjected to smoothing so as to obtain processed acceleration; effective characteristic acceleration is obtained from the processed acceleration, and time position of the effective characteristic acceleration in the preset acquisition time is recorded, and a first time window taking the time position of an object characteristic acceleration in the effective characteristic acceleration as the center is determined; it is determined that whether the processed acceleration possesses periodicity based on similarity of processed acceleration waveform in the first time window with processed acceleration waveform in a second time window; if the processed acceleration possesses periodicity, the time length of the first time window is determined to be a step period, and step calculation of the processed acceleration is carried out according to the step period. The step calculation method is capable of reducing miscounting or missing counting in step calculation, and increasing accuracy of step calculation.