Measuring and analysis technology based on fast fourier transform was implemented for the problem of noise signal of pineapple leaf fiber extractor by disassembling the hood, concave board and residue discharge sheet, respectively. The main factors that increased aerodynamic noise were in sequence of concave board, the hood and residue discharge sheet . To control the noise level, the gap between the blades and the hood was increased from 20 mm to 40 mm and some holes were drilled on both sides of the hood. The extractor noise was decreased from 93.7 dB(A) to 87.8 dB(A), and the methods meet the requirements of hearing protection of operators.