A 13 lobe nozzles with a 5×5 fork row aero-engine staged combustion chamber water model test bench was set up to achieve different working loads by changing the staged injection mode of each nozzle. The aerodynamic flow field characteristics of the model combustion chamber under two kinds of loads, such as 30% and cruise, were studied by water simulation tracer experiments and mathematical modeling under the two-stage and three-stage combustion organization modes. The aerodynamic characteristics of complex vortex structure and vorticity induced by each level of flap nozzle in size, shape, interaction and evolution were studied by experiments and numerical simulation for the two fractional combustions when the oil and gas ratio under the two loads was changed. The results showed that the vortex structure of the two kinds of staged injection modes can be divided into initial section, transition section and development section. The vortex systems have undergone evolution and interaction from independence to merger and reorganization, and then evolve into new vortex systems. When the oil?gas ratio increased, it had a greater impact on the transition of the two kinds of staged injections. The calculation results of the air and water model flow fields were consistent with the experimental results, which verified the feasibility and credibility of the research results.