Highly porous fibrous assembly made by kapok and hollow PET fibers was prepared by the air-laying-bonding method, and used as the interceptor for oils on static and running water. SEM showed that the vast majority of kapok and PET fibers in the assembly was intact and retained their hollow lumens, with the assembly's porosity high to 98.03%. Oil sorption tests exhibited that kapok/PET assembly could absorb 63.00g/g of vegetable oil and 58.50g/g of used motor oil, with high oil retention after 24h dripping. In static condition of oil interception, the two oils started to leak at around 20min for 10-mm thick kapok/PET wall. The time for that was prolonged with increasing the thickness of kapok/PET wall. After oil breakthrough, continuous oil leaking took place. The typical leakage was divided into three stages in which oils leaked separately in sharply increased rate, reduced rate and finally gently. In running condition, oils leaked in markedly quicker way than that in static condition, with initial leakage of oils shortened to less 6min when the water ran at 60.35ml/s. The leakage of oils was considerably accelerated with increasing running rates.