Abstract: The impact of on-the-spot noises and main frequency noises produced by wide belt sander on workers' psychological load were analyzed and evaluated for the first time from the aspect of the influence of noises on electroencephalograms(EEGs) and subjective comfort.The wide belt sander was used as the noise source,and the experiments of EEGs and the survey of subjective evaluation were carried out in a quiet environment and exposed to noises separately.Finally,the influence of noises on the workers' psychological load was discussed based on the change of human EEGs and the subjective evaluation results.The study focused more on the impact of noises on the labor security from the aspect of engineering psychology.Resultsshow that noises of 67 and 1 422 Hz increase β and Fast α most,and worker's irritability to the environment rises when exposed to noises.Mid α and Slow α increase greatest after the influence of 446 Hz noise and recover fastest.The noises at the control center have similar evaluation to those of 67 and 1 422 Hz.