International Journal of Information Studies Amin Shojaatmand1, Navideh Saghiri, Sattar Hashemi, Mashallah Abbasi Dezfoli 3 4 2011 https://www.dline.info/ijis/fulltext/v3n4/ijisv3n4_1.pdf In Data Grid, the selection of replica is critical for users and jobs to access a data file. Our research is mainly focus on replica selection mechanism in order to achieve best performance. This research proposes new replica selection base on ant colony optimization to improve average access time. We use grid simulator OptorSim to evaluate our approach. Our new algorithm can yield better performance result compare with other ant algorithm in this subject.