Objective To propose ultrasonic deep rolling with longitudinal-torsional vibration (UDR-LTV) based on ultrasonic machining with longitudinal-torsional vibration and ultrasonic deep rolling, and to study the effects of processing parameters on surface strengthening, so as to verify the application effect of the two-dimensional ultrasonic vibration machining technology in the field of surface strengthening technology. Methods Conventional deep rolling (CDR) and UDR-LTV were applied using the single factor experiment to process aluminum alloy 6061-T651 respectively, then the surface micro-hardness was tested by each set of parameters with the MH-5 digital hardness tester to investigate the influence of static pressure, rotate-speed and feed amount on the surface micro-hardness. The results of the two processing ways in the experiment were compared. Results Within the set parameters, the surface micro-hardness obtained by UDR-LTV was larger than that of CDR under the same processing conditions. The surface microhardness increased at first then decreased with the increase of static pressure and rotate-speed, and decreased at first then increased and decreased at last with the increase of feed amount by UDR-LTV. The surface micro-hardness and static pressure showed an approximate linear relationship, and the surface micro-hardness increased at first then decreased with the increase of rotate-speed, and reduced all along with the increase of feed amount by CDR. Conclusion It is proved that aluminum alloy 6061-T651 may be more effectively strengthened when treated by UDR-LTV.