Summary Background To investigate the efficacy of continuous and pulsed ultrasound (US) in the management of knee osteoarthritis (OA). Design This systematic review and network meta-analysis covered 12 trials in total. Electronic databases including MEDLINE, Embase and Cochrane Library were searched through to identify randomized controlled trials comparing the two modes of US with control interventions (sham or blank) or with each other. Bayesian network meta-analysis was used to integrate both the direct and indirect evidences on treatment effectiveness. Results Pulsed US (PUS) is more effective in both pain relief and function improvement when compared with the control group; but for continuous US (CUS), there is only a significant difference in pain relief in comparison with the control group. In addition, no matter in terms of pain intensity or function at the last follow-up time point, PUS always exhibited a greater probability of being the preferred mode. However, the evidence of heterogeneity and the limitation in sample size of some studies could be a potential threat to the validity of results. Conclusions Our findings indicated that PUS, with a greater probability of being the preferred mode, is more effective in both pain relief and function improvement when compared with the control group. However, CUS could only be considered as a pain relief treatment in the management of knee OA. The findings also confirmed that none of these modes is dangerous. Level of evidence Level II, systematic review and network meta-analysis of randomized controlled trials.