A shock absorption apparatus for a treadmill interposed between a lifting frame and a running board, comprising: a) a fixing tube having one end fixed on the lifting frame, a positioning member, a locating gear, a locating member, and a damping spring being placed into the fixing tube one after another; b) a sleeve mounted at the external circumference of the fixing tube; c) a push tube having one end fixed on the running board, the other end of the push tube being extended into the fixing tube in such a manner that the push tube is screwed with a locating gear and a locating member, the locating member, the sleeve, and the push tube being interlocked by means of a locating screw; and d) a shock absorption regulator having an adjusting gear set, a motor, and a housing, the adjusting gear set and the motor being received within the housing, the housing being mounted by a fixing member on the external circumference of the sleeve, a drive gear of the adjusting gear being engaged with the locating gear. Unlike the conventional structure having a bad damping effect and being incapable of adjustment of the damping effect, an excellent damping effect is ensured by the configuration according to the invention. Moreover, a continuous adjustment of the damping action is achieved.