From the solution steps, there are two main phases, pairing generation and pairing optimization, to provide a solution for the daily crew pairing. Most researches use enumeration way in the former phase. The drawbacks of enumeration are the solution space will be limited and time consuming for planners. Therefore, we use the genetic algorithms (GA) to integrate both phases. Genetic algorithms, first introduced by Holland, were later improved by many researchers (Holland, 1975; Leung and Wang, 2001; Deb, 2003; Tsai et al., 2004). GAs possess the global explorer capabilities and have been successfully used in many multi-objective researches (Lee et al., 2007, Chou, 2008).