An electro-hydraulic variable valve lift apparatus may include a valve unit housing of which a guide protrude portion is formed therein, a main piston which is slidably disposed in the valve unit housing and defines a valve adjusting oil chamber with the valve unit housing, a main spring which is disposed within the valve adjusting oil chamber and elastically supports the main piston on the guide protrude portion, a dependent piston which is slidably disposed within the valve unit housing, is guided along the guide protrude portion, reciprocates according to reciprocation of the main piston, and opens a valve, and a main oil supply portion which selectively supplies hydraulic pressure to the valve adjusting oil chamber.