Time efficiency of key establishment and update is one of the major problems contributory key managements strive to address. To achieve better time efficiency in key establishment, we propose a Location-based Huffman (L-Huffman) scheme. First, users are separated into several small groups to minimize communication cost when they are distributed over large networks. Second, both users computation difference and message transmission delay are taken into consideration when Huffman coding is employed to forming the optimal key tree. Third, the combined weights in Huffman tree are located in a higher place of the key tree to reduce the variance of the average key generation time and minimize the longest key generation time. Simulations demonstrate that L-Huffman has much better performance in wide area networks and is a little better in local area network than Huffman scheme.