A novel 2×2 polymer electro-optic switch was optimized and simulated based on two-group five-serial-coupled microring resonator and their cross-coupling with two channel waveguides. Detailed structure, theory and formulation were available to characterize the output powers of the switch. For realizing boxlike spectrum (drop port) as well as low crosstalk and insertion loss, resonance order and coupling gaps were optimized. Analysis and simulation on output powers and output spectrum indicated that, a switching voltage of about 4.0 V was desired to realize the exchange between cross-state and bar-state; the crosstalk under cross state and bar state were extremely low as －66 dB and －54.7 dB, respectively; the insertion losses under the two operation states were 2.34 dB and 0.24 dB, respectively. For the drop port, the 10%~90% rise time and fall time were estimated to be 15 ps and 90 ps, respectively, under the operation of 1 GHz switching operation.The bending radius of each electro-optic polymer microring was as small as 19.45 μm, leading to ultra-compact size of only 0.407 mm in both length and width, which was nearly 1/10 of the length of Mach-Zehnder interferometer or directional coupler type polymer electro-optic switches. Consequently, because of small footprint size and extremely low crosstalk, this switching configuration can be densely integrated onto optoelectronic chips, and thus it possesses potential applications in optical signal control in optical networks-on-chip.