The investigators targeted the patients with knee OA. After treatment in 4 groups - individualized acupuncture treatment, standardized acupuncture treatment, sham-needle treatment, and waiting groups - the investigators will compare the effects of pain relieving and daily performing improvement. So the investigators will confirm the efficacy of acupuncture, and further the best treatment method. In addition, the investigators are going to evaluate the safety of abnormal reaction during the treatment.