Abstract: In this paper the -reasonable design on the uniform fluid distribution device for radial flow reactors is explored. The flow of fluid in the main chan nel may be described by the modified momentum equation where p, Y/g, w, , DB and x denote fluid hydrostatic pressure, density of fluid, velocity through the main channel, tube friction coefficient, equivalent diameter of main channel and length of main channel respectively. The momentum exchange coefficient k has been measured. In divided flow channel k ranges between 0.65 and 0.72, but in combined flow channel it is a little, more than unity. The hydrostatic pressure distributions in the main channels have been analyzed. According to the magnitude of friction resistance item relative to the momentum exchange item, four flow models in the divided flow channel have been presented Condition Model Momentum exchange is in control Friction resistance is in control Momentum exchange is dominant Friction resistance is dominant In the divided flow channel the tendency of variance of the hydrostatic pressure varies with the model, because the momentum exchange item and the friction resistance item have contrary effects on hydrostatic pressure. But in the combined flow channel their effects are consistant and they always cause the hydrostatic pressure to decrease. In order to reduce the difference of variance of the hydrostatic pressure between the divided flow channel and the combined flow channel in the radial reactors, it is reasonable to adopt "IT" type distribution as the. divided flow channel is controlled or dominated bythe momentum exchange. On the other hand, the "Z" type distribution would be more suitable when the divided flow channel is controlled or dominated by the friction resistance, A reasonable ratio of the cross section of the divided flow channel to that of the combined flow channel has been proposed in accordance with the various flow models. The resepective resistance coeffi-cients of the side flow through the hole for the divided flow channel and the combined flow channel have been determined. The resistance coefficients depend essentially on the ratio of the velocity through the hole to the velocity along the axis direction in the main channel and the ratio of the thickness of the wall to the diameter of the hole. The holes along the axis direction may be arranged equally or unequally according to the degree of difference in the variances of the hydrostatic pressure between the divided flow channel and the combined flow channel. Several problems such as the selection of the initial pressure drop through the hole, the catalyst seal and the axis flow inside the radial bed have been discussed. The design method has been used in various situations and the predicted results have been obtained.