The invention provides a step counting method which comprises the steps: accelerations in all directions are obtained; a composite acceleration is calculated; a judgment of whether run or walk is made according to the amplitude of the composite acceleration. In the step counting method, an acceleration testing method adopted can distinguish the running of the human body from the walking of the human body, and a real walking from other disturbance. Besides, the invention also provides a step counting device and methods for rectifying stride and estimating moving distance.