The posterior slope of tibial plateau in 25 pairs of Chinese cadaveric tibia was studied. A digital photograph of the lateral profile of each cadaveric tibia was taken, and the posterior slope angles of medial and lateral plateau relative to the anterior tibial cortex were measured. The posterior slope of the medial plateau was 14.8 degrees, and the posterior slope of the lateral plateau was 11.8 degrees. Lateral radiographs of each cadaveric tibia were taken, and the posterior tibial slope angles relative to simulated extramedullary and intramedullary alignment were determined. With radiographic measurement, the posterior slope was 11.5 degrees using intramedullary method, and it was 14.7 degrees using extramedullary method. The posterior slopes increased with the presence of degenerative changes.