The measurement and control of dust concentration in mine environment is always a difficult problem for the safety development of mining field.The uniform spatial distribution of experimental dust was observed by an internal-cavity circulation system, and a two-optical fiber differential measurement method was adopted to solve the problem of dust precipitation on the surface of the detection window, both of which could contribute to the safe and real-time monitoring of dust concentration in the downhole location. Thus, taking cornmeal powder as the research example, the measured value of dust mass concentration was calibrated by calculating the ratio of the dust mass concentration to attenuation coefficient under 5 different injection masses, which led to a basically agreement of the measured results and the ideal calculated value in the curve. It is found that the two-optical fiber differential measurement method can effectively solve the dust problem on the surface of the detector and can provide a reference for the engineering application of dust-concentration optic fiber monitoring technology in the mine environment.