Abstract: Energy consumption is an important consideration in Cooperative Spectrum Sensing (CSS). In order to reduce the data reporting energy and thus prolong the lifetime of Secondary User (SU) with energy constraint in Cognitive Radio Network (CRN), a novel censor-based CSS scheme is proposed. The philosophy of the proposed scheme is to let an SU to report only if the sensing result differs from its previous one. The reporting energy in the proposed scheme is investigated along with comparison, and the spectrum sensing period and energy detection threshold are then optimized subject to sufficient protection to the Primary User (PU). Theoretical analysis and simulation results show that, the proposed CSS scheme reduces the reporting energy significantly without any loss in sensing performance compared with existing studies.