The invention provides a small-scale ion collection type dust monitoring device based on an alpha radioactive source. The small-scale ion collection type dust monitoring device based on the alpha radioactive source comprises a sensing system, a measuring system and a data processing system, wherein the sensing system is tubular, used for attracting air and measuring the dust content in the air andcomprises an air inlet segment, an air outlet segment and an electric field segment, wherein the electric field segment is located in the middle, a cathode wire is arranged on the axis line of the electric field segment, and absorbing barriers are arranged on the inner side wall of the circumference; the measuring system provides designated negative pressure for the cathode wire, and meanwhile, the negative pressure variable quantity of the cathode wire is measured; and the data processing system receives a negative pressure variable value, calculates a voltage (an induced current) output bythe cathode wire, obtains a linear relation of the dust concentration and the induced current of a detection site, and then obtains a dust concentration value of a current detection site. According tothe small-scale ion collection type dust monitoring device based on the alpha radioactive source, the radioactive isotope characteristic and ion collection type sensor technology are combined organically, a novel working site productive dust monitoring sensing system is formed, the sensing system has very high sensitivity, and the lower limit of dust with the particle size of 1 [mu]m is about 0.1mg/m<3>.