The invention discloses a method for determining a near-field phase center of an antenna with a complex structure. The method comprises the following steps: 1) performing electromagnetic emulation modeling on the antenna with the complex structure; 2) determining the electromagnetic characteristic of the antenna with the complex structure; 3) determining a field value on a extrapolated boundary surface which encircles the antenna; 4) determining an auxiliary function of a reference observation surface of the phase center; 5) determining the curvature radius of an equiphase surface; 6) determining the near-field phase center of the antenna with the complex structure.