Knee osteoarthritis (KOA) is a major cause leading to chronic bone and muscle pain. Extracorporeal shock wave therapy (ESWT) has been applied in treating KOA in recent years. From April 2016 to April 2017, 82 patients were diagnosed with KOA that received ESWT were selected as the ESWT group. The treatment parameters were as follows, 2.0?bar, 0.25?mJ/mm, and 8?Hz/s for twice a week for 4 weeks continuously. In addition, 104 patients receiving oral administration of nonsteroidal anti-inflammatory drugs (NSAIDs) from April 2015 to April 2016 were also selected as the NSAIDs group. At 4, 8, 12, and 16 weeks upon the completion of treatment, the Visual Analogue Scale (VAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were adopted to evaluate the changes in pain and function of patients in both groups. For the ESWT group, the 50-m quick walk time and gait analysis were applied to observe the functional recovery at 4, 8, 12, and 16 weeks upon the completion of treatment; meanwhile, patients were followed up by magnetic resonance imaging (MRI) at 24 weeks upon the completion of treatment, so as to observe the cartilage changes. Differences in VAS, 4, 8, and 12 weeks after treatment were statistically significant compared with that before treatment (4.59?±?0.5, P?<?.05; 2.55?±?0.5, P?<?.05; 4.39?±?0.49, P?<?.05). Differences in 4, 8, and 12 weeks after treatment were statistically significant compared with that before treatment (90.41?±?6.64, P?<?.05; 59.94?±?3.19, P?<?.05; 90.49?±?6.87, P?<?.05). Gait analysis suggested differences in 50?m walk time, walking speed, swing phase, and stance phase 8 weeks after treatment were statistically significant compared with that before treatment (36.23?±?4.08, P?<?.05; 1.25?±?0.09, P?<?.05; 58.56?±?0.87, P?<?.05; 41.44?±?0.87, P?<?.05). Differences in the VAS and WOMAC at 4 and 8 weeks after treatment between ESWT group and NASIDs group were not statistically significant. The ESWT has potential in reducing pain and improving knee function, and the therapeutic effects may peak at 8 weeks after the completion of treatment. Further research is needed to arrive at a definitive conclusion.