This paper describes the fabrication, size measurement, and uncertainty evaluation for the monodisperse polystyrene latex (PSL) particles with nominal sizes of 100 nm, 300 nm, and 500 nm using the homemade electro-gravitational aerosol balance (EAB) method. In the measurement system, charged particles are classfied by the Differential Mobility Analyzer and introduced the single charged particles into the space between horizontally placed planar electrodes. The evaluation of the number of survived particles after a period of settling time can lead to determine the particle mass according to the balance between the electrostatic and gravitational forces exerted on the charged particles. And the particle size is calculated with a known density. The main contributed error sources of measurement uncertainty by EAB are survival rate curve fitting and producibility. The measurement results of homemade PSL particles are 109.0 nm +/- 1.2 nm, 284.4 nm +/- 0.92 nm and 529.4 nm +/- 1.3 nm, respectively.