Pain is the main symptom of osteoarthritis. Determining the distinctive features of pain in knee osteoarthritis allows for an accurate diagnosis. This article gives a review of the results from research work on the typical features of knee osteoarthritic pain. The mechanics and biochemical causes of pain are described including both bone and synovial biochemical symptom-related factors. The relationships between knee pain, various imaging techniques and pain mechanism are also identified. Finally, the used pain scales are presented.