Optofluidics has become an appealing platform to fuse photonics and microfluidics for a large variety of applications. Here we demonstrated the use of optical fiber grating devices in the development of optofluidic devices, sensors and tunable lasers. A miniature microfluidic flowmeter and a microfluidic biochip are demonstrated through on-chip integration of microfiber Bragg grating and long-period grating, respectively. An optofluidic tunable mode-locked fiber laser using a microfluidic chip integrated with long-period grating will also be presented.