Abstract: Based on fully investigation and research of pigging solutions of subsea tieback flowline for the domestic and foreign deepwater oil and gas field development projects, according to the specific characteristics of deepwater oil and gas development project in the South China Sea, the comparative analysis for different pigging solutions of subsea tieback flowline is carried out, and pigging solutions adoptable for the South China Sea projects are obtained. Different pigging solutions have different advantages, disadvantages and application ranges. The scheme of launching and receiving pig on the existing facility is widely used for projects with high pigging frequency, while the subsea launching pigging solution is used for projects with low pigging frequency. OLGA software is used to simulate the pigging operation of a certain deepwater gas field in the South China Sea, and multiphase transient flow characteristics during pigging are analyzed. The results can be used to conduct flow assurance design and pigging operation in subsea tieback flowline to existing facility.