Knee is one of the biggest and most complicate joint in human body. With the development of the knee surgery, It is a trend for researching the medial collateral ligament in the future that how to attain the functional anatomy and biomechanics quantifiable characteristic. The research of the medial collateral ligament functional anatomy focus on: how to maintain the stability of the knee、how to limit the external rotation of the tibia、the difference of the stress location in MCL when knee bend 、rotate and walking. The research of the medial collateral ligament biomechanics focus on: content、linearity hardness、viscoelastic properties,etal. This paper reviewed recent advancements on the study of medial collateral ligament functional anatomy and biomechanics, especially on the quantifiable characteristic.