Focusing performance analysis of 3D seismic geometry applies common focus point (CFP) theory to carry out geometry design and evaluation. By focusing imaging on shot points and receiving points, the resolution and clarity of focusing imaging is analyzed to guide geometry design. After analyzing the impact of bin size, fold, array length and the distance of receiving points on focusing resolution and clarity, the focusing performance of geometry was evaluated. The actual data processing result of Machang area is matched well with the achievements of focusing performance analysis, which proves that focusing performance analysis of 3D geometry is reasonable and can be used to guide geometry design.