The dynamic process of load plasma impacting on the foam cylinder was studied by two-dimensional radiation hydrodynamics simulation, and the influence of the shape of load plasma with disturbance on the radiation temperature in dynamic hohlraum was explored. The results show that Rayleigh-Taylor fluid instability will be generated after the disturbed load plasma impacting on the foam, and the development of RT instability will lead to the radiation leakage in the light-thin region of the load plasma, which will reduce the radiation temperature in the dynamic hohlraum. The larger the amplitude and the wavelength of disturbance in the load plasma, the more serious radiation leakage occurs, and the lower the radiation temperature will be in the dynamic hohlraum under the same kinetic energy loading condition.