The aim of this paper is to present the theory and design of an electrostatic particle collector for indoor air purifier. In this study, a mathematical model was developed to study the characteristics of the inside electric field and the analysis of the collection efficiency of the collector. It was found that the electric field inside the collector is uniform distributed along the radius of the 4 discharge electrodes to outer tube. The maximum electric field strength was found around the 4 discharge electrodes, about 4.1 × 105, 4.6 × 105, 5.2 × 105 V / m for a discharge voltage of 8, 9 and 10 kV, respectively. The results showed that the collection efficiency was higher than 99 % of particles with a diameter larger than 1.5, 7 and 18 μm for an air velocity of 0.1, 0.5 and 1 m/s, respectively. Collection efficiency was also high when the voltage discharge electrodes and the particle diameter are higher as well as the air velocity is lower.