In the process of practicing Taijiquan, the symptom of knee pain will happen from time to time, the pain symptom is closely connected to such factors as the movement postures, technical movements, contraction force of lower limb muscles and ligament traction. This research is designed to analyze and compare the sports biomechanics between the trainees with the symptom of knee pain and Taijiquan coaches with skilled technology through the experimental method; the results show that the result of knee pain symptom has something to do with the unscientific training and failing to master the correct technical essentials.