Fiber Bragg grating (FBG) fabrication on a draw tower can form a one-dimensional array of FBGs on a single fiber without welding spot between gratings, and is beneficial to build a massive sensor network. Phase mask method is employed to fabricate FBG online on a draw tower, by which we can precisely control the Bragg wavelength of FBG. A set of device is developed according to the characteristics of inscribing FBG by using phase mask method and the requirements of writing FBG on a draw tower. An array of 164 FBGs is produced on a single fiber by using this device.