The invention provides a task allocation method and device for a clustered wireless sensor network based on a contract net. The method comprises the following steps: S1, a supervisor sends out task invitations to nodes of which the residual energy value is more than an energy threshold; S2, participant nodes respectively give out initial quotations based on the achievable task completion and the residual energy; S3, prior to the maximum negotiation time, an administrator and each participant node make a price concession negotiation according to a Powell convergence mechanism based on time t, the negotiation can be successful when the quotations of both parties making the negotiation meet preset conditions, and a corresponding participant node is defined as a contract object; and S4, the administrator allocates the task to the successful bidder node and sends out a notification indicating that the task has been allocated to all the participant nodes. By using energy as the negotiation participation threshold, the invention lowers the negotiation complexity and simultaneously balances the energy of all the nodes. Besides, the method and device provided by the invention also achieves a certain balance between the task allocation instantaneity and the task allocation efficiency and can realize the stratified task allocation of a complex task.