In this Letter, a 16 channel 200 GHz wavelength tunable arrayed waveguide grating (AWG) is designed and fabricated based on the silicon on insulator platform. Considering that the performance of the AWG, such as central wavelength and crosstalk, is sensitive to the dimension variation of waveguides, the error analysis of the AWG with width fluctuations is worked out using the transfer function method. A heater is designed to realize the wavelength tunability of the AWG based on the thermo-optic effect of silicon. The measured results show that the insertion loss of the AWG is about 6 dB, and the crosstalk is 7.5 dB. The wavelength tunability of 1.1 nm is achieved at 276 mW power consumption, and more wavelength shifts will gain at larger power consumption.