Blockchain has been widely used in many fields such as bitcoin, smart contract, supply chain. However, because of the high requirement of computation and energy resource in mining process, blockchain application is restricted in mobile environment. In this paper, we introduce edge servers offered by Edge Service Provider into mobile blockchain network. Thus mining task can be offloaded from mobile devices to the edge server. Since there is competition among users, we propose an auction-based model for edge server resource allocation. Moreover, in order to maximize the revenue of all mobile users, we design a mechanism to achieve the allocation strategy and pricing rule for Edge Service Provider. Considering different resource demands, bids and usage time, we use Benders decomposition to get the dynamic resource allocation strategy. We evaluate the performance of the proposed auction model through extensive simulation. Results show that dynamic allocation can solve the resource allocation problem for Edge Service Provider and will get higher revenue with more winners than fixed allocation.