Jamming attack is one of the major threats in cognitive radio networks (CRNs). In this paper, we propose an anti-jamming channel hopping algorithm, Tri-CH, for CRNs. Tri-CH adopts random jump pattern (i.e., hops randomly over channels) to achieve high security level and reception mode stay pattern (i.e., stays at a channel for receiving packets only) to guarantee bounded time to rendezvous. Tri-CH operates without pre-shared secrets and role pre-assignment. Hence, Tri-CH is applicable to large networks, where nodes join and leave the network frequently, and may play the sender role and the receiver role, simultaneously. According to the theoretical analysis, Tri-CH outperforms in terms of maximum time to rendezvous under jamming attacks.