This paper demonstrates surface plasmons (SPs) enhanced MgZnO ultraviolet (UV) photodetectors grown by a radio frequency (RF) magnetron sputtering technique, and the magnesium concentration is 30%. Predominantly, well-defined Au NPs with different sizes were produced embedded in MgZnO thin films. Notably, at 30V applied bias, the proper combination MgZnO/Au NPs (40s), responsivity as high as 341.08A/W is achieved after optimizing the process. Impressively, the excellent comprehensive performance of MgZnO/Au NPs UV photodetectors should have great applied potential, a physical mechanism is given to explain the above results.