Abstract As one of the largest discovered gas fields in China, Kela 2 gas field has proven geological reserves of more than 200 billion cubic meters, with a maximum annual gas production of approximately 12 billion cubic meters. After 18 years development, Kela 2 gas field is now in the middle-late development period. At present, the gas field has experienced many development challenges, among which early water flooding and inhomogeneous water invasion are the main reasons for the production decline in Kela 2 gas field. Based on the abundant geological and performance data, a fine 3D geological modeling is built to accurately describe the structure, matrix properties and fracture in Kela 2 gas field, and then analyzes the characteristics and causes of water invasion. The research shows that faults, fractures, high permeability zone and interlayer are the main controlling factors of water invasion in Kela 2 gas field. And the water invasion can be divided into three patterns, (a) Vertical channeling-lateral invasion, (b) Edge water lateral invasion, (c) Bottom water coning. On the basis of water invasion study, development countermeasures are put forward to provide support for long-term stable production and efficient development of Kela 2 gas field.