Abstract: Particle image velocimetry(PIV) was used to experimentally study the cold flow field of a model rectangular trapped vortex combustor(TVC) in this paper.The influence of mainstream velocity and mainstream structure(with or without flame stabilizer) on the behavior of vortex in the cavity was analyzed.It shows that the dimension and shape of vortex,location of vortex center are not sensitive to mainstream velocity.But the swirling strength and circulation mass flow rate in cavity increase with mainstream velocity.The vortex center is located in the center of cavity without stabilizer.The vortex center moves backward at the symmetry section,but moves forward at the stabilizer section.The result can provide references for TVC design and performance optimization.