Although there have been remarkable advances in the treatment of hepatocellular carcinoma (HCC), the prognosis remains poor in those with advanced stage and more effective therapeutic options are urgently needed. Lenvatinib (Len), a multiple receptor tyrosine kinase inhibitor, is an emerging molecular targeted agent for HCC, whose immunomodulatory activities have been investigated. However, Len utilization is limited because of its low metabolic stability, poor bioavailability and dose-dependent toxicity, rendering its direct use insufficient for immune modulation. Stimuli-responsive nanoparticles, which are drug-targeted delivery platforms for on-demand drug release, facilitate deeper and uniform tumour penetration, providing alternative solutions to overcome current limitations. Ultrasound (US) exhibits superior tissue penetration abilities and can produce reactive oxygen species (ROS) at the tumour site to treat deeper tumours. In addition, US serves as an excellent and selective drug delivery mediator for tumour treatment. Herein, we designed US-triggered lenvatinib nanoparticles (Len-RNPs) for selective drug delivery that utilize US-triggered ROS to induce in situ oxidation reactions, resulting in nanoparticle disintegration. Len-RNPs mitigate the toxicity of Len and effectively trigger robust systemic anti-tumour immune responses in a H22 tumour model, resulting in a tumour suppression rate of 95.7%, with 60% of mice being cured. Our study elucidates a novel and precise strategy of combining Len and US therapy for enhanced HCC immunotherapy.