Two beams in the traveling the same path with opposite directions makes it is more suitable for stability beam combination. As a passive and separation device, spiral phase plate has the advantages of high efficiency and low working conditions. It has important significance to propose a method to generation vector beam with Sagnac interferometer and spiral phase plate combination. By analyzing the evolution of the orbital angular momentum states and the polarization states of the beams in the Sagnac interferometer, an isosceles right triangle optical structure beam combination system was designed. Without half wave plate, the optical structure was more compact and stability. The order of generated vector beams were checked with rotation of polarizer. The experimental results confirm the high stability and high efficiency of the combined beam method.