A new hydraulic cavitation‐assisted epoxidation scheme was developed by using a cost‐effective, environment‐friendly, and recyclable solid‐acid catalyst. SnO2‐Al2O3‐NiO/SO42− solid‐acid catalysts were prepared using co‐precipitation and impregnation methods, which were characterised by several techniques and analysed using the Hammett acidity function. The prepared catalysts were found to have a large specific surface area (53.95 m2/g) and abundant acid sites (94 μmol/g). Exhibits higher stability and more effective catalytic activity compared with H2SO4. Under the optimal reaction conditions, the relative conversion to oxirane of 86.97% was obtained in only 1.5 h of reaction time. Moreover, the catalyst could be easily separated and showed satisfactory catalytic activity after five reuse cycles. The current work has clearly demonstrated that the application of hydraulic cavitation technology to the solid‐acid‐catalysed epoxidation reaction of soybean oil can shorten the reaction time, increase the relative conversion to oxirane, and be a viable method with promising applications.