Cognitive radio networks (CRNs) have emerged as a critical technique to enhance the utilization of licensed channels. In CRNs, each secondary user (SU) should not interfere the co-locate incumbent networks. For this purpose, before data transmission, SUs should rendezvous on an available channel (i.e., idle and licensed channel) for establishing a link or exchanging control information. However, implementation of rendezvous is challenging since SUs are not aware of the presence of each other before rendezvous and available channels sensed by each SU may be different. In this paper, we proposed a fast rendezvous channel hopping algorithm (FRCH), which can guarantee rendezvous within 2N 2+N timeslots under asynchronous environments, where N denotes the number of licensed channels in a CRN.