Abstract: The theoretical analysis, process calculation and economic comparison on the internal coating to be used in West-to-East Gas Pipeline are conducted. The results show that after the pipeline is applied the internal coating, several benefits can be obtained, such as enlarging the station spacing, cutting down the numbers of compressor station, decreasing pigging frequency and reducing the power consumption, which can greatly reduce the fixed investment and operating cost. Therefore, it would be economically ratioanal if internal coating was used in West-to-East Gas Pipeline.