Abstract: For obtaining the distribution characteristics of flow velocity inside a radial diesel particulate filter (DPF) which can rotate, flow computation software was used in simulating distribution characteristics of flow velocity. Several influence parameters such as flow velocity, diameter ratio, divergence angle and the length of filter were investigated. Under the condition of inlet velocity of 50 m/s, the flow velocity of calculation section was measured. Through comparison between measured results and simulated results, the maximal error of flow velocity was 3.2 m/s, and the simulated results was reliable. As the results, distribution uniformity of flow velocity could be improved by reducing inlet velocity, diameter ratio and divergence angle, and increasing the length of filter. Study on the distribution characteristics of flow velocity inside the DPF is very significant for controlling particle regeneration, improving utilization ratio and operating life of the DPF.