Multipath is a sought-after mechanism to achieve reliability along the error-prone channel in wireless sensor networks. However, its benefits are not easily explored because the critical energy constraints and the multipath interference. In this paper, we first prove that finding several disjoint paths with minimum energy consumption is an NP-complete problem, then give the near-optimal solution on how to choose path based on the accurate energy model. Furthermore, we make use of the multi-frequency characteristic of CC2420 radio and propose IEMM-FA to minimize interference and energy consumption of multiple paths. Simulation results verify its performance.