Abstract: When encounters bad weather, airport capacity is far exceeded by the demand and the resulting delays are a financial and psychological burden for airlines and passengers. CDM(collaborative decision making) GDP(ground delay procedure) is the right Air Traffic Flow Management procedure to settle such special problems. To its main problem-slots allocation, a delay cost coefficient was introduced to current two algorithms. Then two new method had been put forward to handling this problem. In the end, an experimental simulation was done in java language. By using a evaluation function, one can easily find out the best result which meet the decision maker′s request both in total delay cost and equity.