For the characteristic of gas variable mass flow in distribution/collection channels of centrifugal radial fixed bed, the pressure distribution was measured and analyzed in these two channels under both Π-type and Z-type operation modes in a set of cold experimental apparatus. The pressure had an increasing trend along the gas flow direction in the distribution channel, while it had opposite trend in the collection channel. According to the uneven index of pressure distribution in particle bed and the axial distribution of gas radial velocity obtained by Ergun equation, it was found that the centrifugal Π-type was slightly better than the centrifugal Z-type. With the gas radial velocity distribution in particle bed, the flow and momentum balances were applied in the elemental body of the channels to obtain the gas velocity in distribution/collection channels and the local momentum exchange coefficient. Compared to the collection channel, the sensitivity of local momentum exchange coefficient to pressure change was relatively small in the distribution channel. In the distribution channel, the overall momentum coefficient almost unchanged with the operating mode, gas flow rate, and axial position. While the local momentum exchange coefficient was only a function of the flow rate ratio u/u0 (or axial position), which first decreased and then remained unvaried with the flow rate ratio. According to the experimental results, the equation of the local momentum exchange coefficient were obtained by the regression method within 11% error. It was anticipated to provide reference for the calculation of local pressure in the gas channels and the designation of the structural optimization.