An elliptical trainer with variable stride includes a base frame, a swing unit axially mounted at the base frame, a pedal unit axially mounted at the swing unit, a damping unit for providing damping resistance to the swing unit, and a constraining unit including an axle axially mounted at the base frame, a pair of upper cranks respectively affixed to two opposite ends of the axle and a pair of coupling members respectively pivotally coupled between the upper cranks and the swing unit. Mating the constraining unit with the swing unit prevents the swing unit from overswinging, enhancing user safety.