The high demand for wireless sensor networks (WSNs) is growing in different applications. Most WSNs use the unlicensed band (ISM band) which leads to congestion in that band. On the other hand, without damaging the quality of service (QoS) of the network, minimizing the consumed energy is vital in sensor networks design. Cognitive radio-based wireless sensor networks (CRWSNs) afford some solutions to the problem of scarce unlicensed band spectrum. The spectrum sensing is the main function of the cognitive radio networks. In this paper, for maximizing the accuracy of sensing, as well as the energy efficiency of the network, proposed novel method by employing adaptive spectrum sensing. Spectrum sensing is performed by Secondary User (SU) to identify if the Primary User (PU) is idle, then for verifying that primary user is actually idle, sensing the spectrum again is done by secondary user in order to provide better protection for the primary user. Because of CRWSN has a constraint in energy, that adaptive interval of sensing could also, be modified to optimize the energy efficiency of the network according to the different activity of the PU. Simulation results were provided to validate the efficacy of the proposed algorithms to enhance both spectrum sensing performance and energy efficiency