Abstract: Through the field measurement of noise level of 18 gardeners operating the knapsack brush cutter and the shoulder-hanging brush cutter, we calculated the noise exposure metering of every working day during gardeners operating the trimmer line, two-tooth cutting tools, four-gear cutting tools and forty-tooth cutting tools. According to gardeners' working habits, we tested the noise level made by 2 different brush cutters when cutting plants, in order to work out the sound level and sound frequencies when the two brush cutter being operated at a no-load running, low speed and high speed operation. Meanwhile, brain waves of these gardeners were measured and the average power spectra density ratio R between brain wave band α and band β was compared, so that we can analyze the influence of their mental load and make some positive innovations and further suggestions about how to control unnecessary noise for greening department.