Abstract: The ultrasonic surface rolling processing(USRP)was adopted, and the effects of different rolling static pressure and rolling passes on the hardness gradient and microstructure of solid solution ZK60 magnesium alloy were studied by roughness test, micro-structure observation and hardness test. The results show that, the micro-gradient structure and the corresponding gradient hardness changes of the solid solution ZK60 magnesium alloy are obtained after ultrasonic rolling.With the increase of static pressure(150 N, 250 N and 350 N)and rolling passes(6, 9, 12, 15 and 18)of ultrasonic rolling, the surface microhardness and the depth of gradient strengthened layer of the samples also increase, and the surface grains are refined to a certain extent. Meanwhile, the rheological layer formed on the surface micro-structure is more obvious, and the surface integrity of the sample is better. The minimum roughness of the sample is Ra=0.135 μm, and the maximum surface hardness is 130 HV.