Based on recent results on homogeneous polynomially parameter-dependent (HPPD) solutions to parameter-dependent LMIs (PD-LMIs), we investigate, via right-hand side (RHS) relaxations, the stability analysis of polynomial fuzzy-model-based control systems. The PFMB control system under consideration requires that the polynomial fuzzy model and controller share (1) perfect match or (2) un-perfect match of premise membership functions. This paper proposes a new SOS condition via RHS relaxation and reduces the conservatism of existing PD-LMI results. To verify the analytical theories regarding PFMB stability, two examples are demonstrated to show the effectiveness of the proposed approach.