To simulate the radiation transport of the spherical hohlraum with octahedral six laser entrance holes and to study the capsule radiation uniformity, a Monte Carlo method is introduced. For simple analytical models, with different hohlraumto-capsule radius ratios, the capsule radiation uniformity variation rules are studied, and the Monte Carlo calculation results can match the analytical results obtained by the “view factor” method. For more complicated models, such as the hohlraum with shields, it's difficult for an analytical method to be calculated, but is straightforward in the Monte Carlo method. Two models with different radius of the shield have been simulated. Simulated result indicates that the shield greatly influences the distribution of X-rays on the capsule surface, and an appropriate shield can increase the utilized efficiency of X-rays and improve the capsule radiation uniformity remarkably, otherwise, the uniformity might be destroyed badly. So the location and the radius of the shields must be designed carefully in a spherical hohlraum. This research supports the Monte Carlo method that is applicable in the radiation transport simulation of a complicated spherical holhraum.