Polymer Mach-Zehnder thermo-optic switch is fabricated using traditional semiconductor technology.The surface of waveguide is observed by a scanning electron microscopy,and the output near-field spot is displayed on the infrared camera.At a 1 550 nm optical communication wavelength,the output spectrum is shown.The extinction ratio of the switch is －15 dB and the driving power is 16 mW.The switching property of the device is tested with DC bias.The rise time and the fall time of the switch are 1.2 ms and 0.8 ms.