Abstract: Disclosed is a drilling assembly for anatomic anterior cruciate ligament reconstruction and a method therefore. The drilling assembly comprises an endoscopic reamer, a variable position external stopper and a fixed length outer protective sleeve. The endoscopic reamer has dual length markings thereon. The drilling assembly and the method make the tunnel reaming precise and independent of arthroscopic visualization and manual judgments by avoiding over drilling as well as protect the cartilage over the medial femoral condyle and fibers of Posterior Cruciate Ligament during introduction of the femoral endoscopic reamer over the guide wire during anatomic anterior cruciate ligament reconstruction.