【Abstract】ObjectiveTo investigate the effect of high intensity focused ultrasound (HIFU) on the immunity of patients with advanced primary liver cancer (PLC). MethodsForty cases of PLC admitted to our institution from Mar. 2003 to Dec. 2003 were included in this study. Patients were divided into 2 groups and received either HIFU or radiofrequency ablation (RFA) treatment randomly. CD3, CD4, CD8, CD4/CD8, NK, IL-2, TNF were chosen to assess the immune status before and after treatment. The results were compared statistically. ResultsThe survival rate after HIFU was 80.0%, 61.1%, 42.9%, 33.3% at 3 months, 6 months, 9 months and 1 year respectively, which was similar to that after RFA treatment. The changes of immunity parameters of CD3, CD4, CD8, CD4/CD8, NK, IL-2 and TNF were not significant after HIFU treatment. In addition, the differences of those parameters between HIFU group and RFA group were insignificant. ConclusionThere are no detrimental effects on immunity in the early period after HIFU treatment.