As a typical representative of the NP-complete problem, the traveling salesman problem (TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optimization (DLSO) algorithm is proposed to solve the TSP. Firstly, we introduce discrete coding and order crossover operators in DLSO. Secondly, we use the complete 2-opt (C2-opt) algorithm to enhance the local search ability. Then in order to enhance the efficiency of the algorithm, a parallel discrete lion swarm optimization (PDLSO) algorithm is proposed. The PDLSO has multiple populations, and each sub-population independently runs the DLSO algorithm in parallel. We use the ring topology to transfer information between sub-populations. Experiments on some benchmarks TSP problems show that the DLSO algorithm has a better accuracy than other algorithms, and the PDLSO algorithm can effectively shorten the running time.