A microstrip filtering power divider (FPD) with good isolation performance and harmonic suppression is presented. By replacing a simple resistor with a novel distributed stepped-impedance resonator network, better isolation and wider stopband are simultaneously attained. A transmission matrix-based analysis method is then extensively described to determine the circuit geometrical parameters at the synthesis level by facilitating the incorporation of design indexes and structure dimension. A prototype FPD is designed, fabricated and measured. The proposed FPD exhibits a center frequency of 2.2 GHz (f 0 ) with the isolation better than 17dB within the entire passband and a stopband extended to 12 GHz (5.45f 0 ).