As an important optical device for changing the polarization state of an optical signal, a retarder has high polarization conversion accuracy, low cost, and simple algorithm. A new method was proposed for polarization modulation of radial vector optical field using a combination of a 1/4 wave plate and a 1/2 wave plate. The Jones matrix algorithm was used to analyze the modulation mechanism of the dual-wave plate. The polarization evolution law of the light field was represented on a Poincaré sphere, and the correctness of the theoretical analysis was verified through experiments. The results show that the dual retarder structure can realize complex polarization control of radial vector light field, and obtain a vector field with uniform light intensity distribution and regular polarization state distribution.