Abstract: In order to improve the accuracy of dust mass concentration detection in workplaces, it is necessary to further improve the accuracy of dust concentration detection by β-ray. The experimental analysis shows that the intensity of β-ray is volatility, which is one of the factors affecting the accuracy of dust mass concentration measurement; at present, the basic algorithm of β-ray method does not consider the influence of β-ray intensity fluctuation on the accuracy of dust mass concentration test. By adopting the research method of extracting the characteristic values of β-ray intensity fluctuation data signal, the peak-to-peak, standard deviation and envelope mean value of β-ray are used to calibrate and analyze the dust mass concentration respectively, it shows that the resolution is low when using single characteristic value to calibrate dust mass concentration. Based on the experimental study on the fusion of β-ray intensity volatility, an improved algorithm for calibrating the dust mass concentration was proposed. The experimental results show that when the dust mass concentration is from 0.0 mg/m³ to 920.3 mg/m³, the detection error of the basic algorithm is from 8.7% to 14.3%, while the detection error of the improved algorithm is from 5.3% to 10.0%, the accuracy of the dust mass concentration detection direct reader based on the improved algorithm is 4.4% higher than that of the basic algorithm.