The invention provides a method for deleting invalid elements of a hash table and aims at solving the problem of immediate deletion of the invalid elements of the hash table. The method comprises the steps of providing timeout time Tbucket for each hash bucket, providing timeout time Tkey for each key, when insertion and inquiry of different elements are carried out at two time granularities, updating the value of each key Tkey and placing the value of the key accessed latest in a position, having the first priority in access, of the hash bucket, and in this process, examining the keys having the same hash value in the hash buckets according to the setting of the timeout time Tbucket of each hash bucket, for timeout of elements, deleting invalid elements, and meanwhile, checking other key values in other hash bucket elements of the hash table and deleting elements invalid because of timeout.