A lifting and folding device for a running exercise machine comprises an ascending/folding device and an interacting device installed between a base and an exercise platform. By adjusting the ascending/folding device the interacting device is put in a synchronic motion, so as to achieve the effect of adjusting the exercise platform to an uphill, a horizontal or a downhill configuration. Further, the ascending/folding device has a driving device capable of automatically ascending and folding the running exercise machine.