An organic/inorganic hybrid Mach-Zehnder interferometer(MZI) thermo-optic(TO) switch is designed and fabricated by using the negative photoresist SU-8,polymer PMMA and silica as core,upper cladding and lower cladding,respectively.The structural parameters are optimized for assuring fundamental mode propagation,decreasing radiation loss and leakage loss,shortening response time and minimizing power consumption.Fabrication techniques,including spin-coating and wet-etching,are adopted to develop the device sample.Under 1 550 nm,the driving powers at ON state and OFF state are measured to be 0 and 13 mW,respectively,which indicates the switching power is 13 mW.The extinction ratio between ON state and OFF state is 18.3 dB,and under the square-wave switching signal,the rise time and fall time are 126 μs and 134 μs,respectively.Compared with the thermo-optic switches with Si/SiO2 structure and full polymer structure,the proposed hybrid device possesses low power consumption and fast response simultaneously,owning to the advantages,including large TO coefficient for polymer core material,thin upper/under claddings and larger thermal conductivity of silica relative to polymer.