The invention relates to a composite material bulkhead structure four-point bending test method. The method is used for researching influences of different bulkhead structure forms and different long stringer rat hole shapes on stress and strain distribution and bearing capacity of bulkhead structures, assessing the BVID damage bearing capacity of the structures, and verifying residual intensity of the structures. The composite material bulkhead structure four-point bending test method includes the steps that firstly, a test piece is obtained; secondly, a loading scheme is designed; thirdly, a loading test is conducted. The composite material bulkhead structure four-point bending test method can provide technical support for research of researched and in-service civil airplane body composite material bulkhead structures in China, reduce the structural weight, improve airplane properties, reduce application and maintenance cost and improve economic benefits.