Objective：To observe the effect of low intensity pulsed ultrasound（LIPU） on penetration of methylene blue into knee car－tilage of normal rabbit. Methods：5 ml 0.1% Methylene blue solution were injected into both articular cavities of hind legs of nine New Zeland rabbits. One of the hind legs of each rabbit was distributed randomly into treatment group and treated with LIPU，while the oth－er into control group with dummy treatment. All animals were sacrificed after a five-minute LIPU treatment. Cartilages of femur inter－condylar fossa were removed and cut into slices，and the photos were taken under anatomic microscope. The depths of methylene blue penetrating into articular cartilage were measured. Pair matched analysis was performed to learn if there is a signifficent difference between the two groups. Results：Penetration of methylene blue into articular cartilage in LIPU group were deeper than that in con－trol group（P<0.05）. Conclusion：LIPU enhances methylene blue penetration into articular cartilage，which indicates LIPU may improve nutrition supply of articular cartilage.