Theoretical design of a neotype fluidic controlling sensor system based on side-polished optical fiber is proposed. Numerical investigations demonstrate that the higher birefringence and resonance coupling can be achieved by flexible design of the polishing shape and depth in the research wavelength. The fluidic system is beneficial to selective integration of functional materials. The material is integrated into the fluidic system, which can achieve a birefringence up to 6.98×10^-5, and the application of Sagnac thermometer in temperature sensing is studied, and a group of dips with different temperature sensitivities would be observed in the transmission spectra, which is about 1.6 nm/°C by calculating. furthermore, by introducing resonant coupling, single mode single polarization at 1 310 nm is realized. The refractive index (RI) response of the sensing system for a low RI range of 1.39—1.37 is approximately linear, and exhibits a sensitivity of 6 338 nm/RIU. The results show that the proposed neotype fluidic controlling system can be used as a flexible polarization filter or as a potential two-parameter sensor.