The influences on dual frequency capacitively coupled plasma radial uniformity are studied with a newly developed complete floating double probe. It is found that low frequency power, discharge pressure and gap have significant effects on radial uniformity. The results show that a suitable low frequency power, discharge pressure and larger discharge gap can achieve more uniform plasma. Finally, the improved two-dimensional fluid model simulations are performed with the same discharge parameters in experiment. The radial ion density distributions are obtained for different discharge gaps. The results are almost consistent with each other.