Objective To discuss the value about three-dimensional spoiled gradient echo (3D GRE) sequence in the diagnosis of knee joint cartilage injury by observing and analyzing the signal strength of cartilage and the change of the thickness and shape, etc., to provide diagnostic basis for early detection of articular cartilage injury. Methods 200 patients' cases of knee MRI data were collected between18 to 60, they were divided into two groups which was 18 to 40 and 41 to 60 years old respectively and they were both checked by conventional T1WI, T2WI, water fat separation technology (WFS) and threedimensional spoiled gradient echo imaging (3D GRE) sequence of MRI, 5 places of articular cartilage thickness were measured on knee joints and patellar cartilage by sagittal MRI 3D GRE sequence, applying SPSS 19.0 statistical software for statistical analysis with P<0.05 for the difference statistically significant. Results In the inspection of knee joint cartilage lesions, the three-dimensional spoiled gradient echo(3D GRE) sequence image display the cartilage's signal strength, thickness and the clearest shape change with the highest image resolution. Conclusion MRI three-dimensional spoiled gradient echo(3D GRE) sequence is currently the best diagnostic technique in knee joint cartilage lesions. The more serious cartilage damage is, The thinner thickness of cartilage is, and can reduce missed diagnosis and misdiagnosis.