Ni-CeO2 nanocatalyst was synthesized by the reaction of cerium nitrate and nickel nitrate microemulsion with ammonia gas in a rotor-stator reactor (RSR) in this work. The effect of the RSR rotation speed, ammonia gas flow rate and calcination temperature on the properties of the Ni-CeO2 nanocatalyst was investigated, and the catalytic activity of the as-prepared nanocatalyst in the reaction of CO2 reforming of methane was studied. Experimental results indicated that the catalytic activity of the Ni-CeO2 nanocatalyst prepared in the RSR increased with an increasing rotation speed and ammonia gas flow rate, but increased first and decreased then with the increase of the calcination temperature. Due to the excellent micromixing and mass transfer effects of the RSR, the Ni-CeO2 nanocatalyst prepared in the RSR had a smaller size, narrower size distribution and higher catalytic activity compared to that prepared in a stirred tank reactor (STR). Methane and CO2 conversions and CO selectivity in the reforming reaction with the Ni-CeO2 nanocatalyst prepared in the RSR were 15%-25% higher than those with the Ni-CeO2 nanocatalyst prepared in the STR.