Treatment of adult femoral neck fracture is still a great challenge faced by trauma orthopedists. As treatment effects can be infleunced by multiple factors, like age, gender and preoperative physical condition, they may vary with different treatment schemes. Classification of femoral neck fractures plays an important guiding role in choosing a proper treatment scheme and judging the prognosis. The current classic clinical classification systems for femoral neck fractures include Garden, AO/OTA and Pauwels classifications. Since the recent progress in science and technology has put more advanced technologies into clinic application, such as CT, MRI and Digital Subtraction Angiography (DSA), new ways of classification have appeared. However, each classification has its own shortcomings which need to be improved. This paper reviews the research progress in classification of adult femoral neck fractures and their treatment principles.