Under the given constraints, the optimization problems which searches the solution corresponding to the maximum or the minimum of an objective function is a very important problem in various fi elds. On the other hand, large-scale optimization problems are very difficult. As a way to explore the approximate solution of such optim ization problem, meta-heuristics has attracted attention. This paper describes the swarm intelligence of meta -heuristics. In particular, Particle Swarm Optimization and Firefly Algorithm are introduced. In addition, for each algorithm, a simple operating analysis results are shown.