Glass reinforced plastic (GRP) pipeline has good characteristics of anti-corrosion, anti-scaling and it is widely used in the oil transportation pipeline. Analyze the water hammer characteristics of GRP pipeline is essential to ensure the safety operation of the pipeline. The water hammer mathematic model for GRP pipeline is built through combing the general water hammer mathematic model and prosperities of GRP pipeline. The solving method of the model is discussed based on the method of characteristic. Ultimately, the simulation results show the GRP pipeline can reduce the peak pressure and pressure fluctuation frequency as well as increase the low pressure caused by water hammer compared with steel pipeline. The GRP pipeline has a better capability to reduce the harms brought by water hammer than steel pipeline.