Abstract;l Dielectric behaviors of spherical polyelectrolyte brushes (SPBs) suspensions with different properties, length brushes under various mass fractions of SPBs and pH of solution were investigated in a frequency range of 40 Hz to 110 MHz. In this paper, the SPBs consist of polystyrene (PS) core and the negative poly(acrylic acid) (PAA) named PS-PAA of different length and cationic poly(2-aminoethylmethacrylate hydrochloride) (PAEMH) chains named PS-PAEMH grafted on the polystyrene (PS) core. Two unique relaxations are found at either about 10 kHz or 1−10 MHz, respectively, the former due to the movement of counterions and the latter resulting from the interfacial polarization. Using dielectric parameters of the high-frequency relaxation and the Cell model, the information about the brush length, the volume fraction, the electrical and phase parameters of the SPBs and the bulk solutions can be obtained. The surface conductivity of SPBs, the Zeta potential, and the fixed charge density in the SPBs also can be derived. While the low-frequency relaxation shows two separate mechanisms when the brushes are collapsed and stretched: tangential movement of counterions along the SPB particles for PS-PAA with different mass fraction; diffusion movement of counterions along the brush between the brush and the bulk solution for PS-PAA with different pH, PS-PAEMH with different mass fraction, respectively. Significantly larger conductivity and relaxation strength are obtained for PS-PAA with longer brushes. PAA brushes exhibit a transition with increasing pH in which the chains are stretched from collapsed to nearly full length under the domination of the equilibrium between the penetration and diffusion of counterions in the brushes. We found that cationic SPB PS-PAEMH, whose brush dissociation degree is bigger than PS-PAA with negative brush in the acidic solution. These findings lay the foundation for different SPBs’ different applications.