Abstract: In order to solve problems of high loss rate and high impurity content in flax cleaning process，a wind screen flax cleaning device was designed.With coupling method of EDEM-Fluent，cleaning process of flax cleaning device was simulated and analyzed，influence law of cleaning device operating parameters on flax seed impurity content and cleaning loss rate was explored，and optimal combination parameters were determined.Based on movement analysis of flax threshing material in airflow field of cleaning device，a simplified model of flax cleaning device was established.Single factor test and orthogonal test were carried out for four parameters of fan wind speed，air flow inclination，vibration frequency and amplitude of cleaning screen.Results showed that fan wind speed，air flow inclination，vibration frequency and amplitude of cleaning screen were significant factors affecting cleaning performance of cleaning device.Mathematical regression model of seed impurity content and cleaning loss rate was established by using Design-Expert software.Optimal working parameter combination was obtained：fan wind speed 4.5 m/s，air flow inclination 4°，cleaning screen frequency 6 Hz，cleaning screen amplitude 9 mm.Under optimal working parameter combination，seed impurity content of flax was 2.97%，and cleaning loss rate was 2.39%.Research results could provide reference for design and optimization of flax cleaning device.