Nowadays, human beings encounter with hug data. Due to development of computer and detector technologies, few terabyte data has been produced. The analysis of these information require the sources whose financial costs cannot be afforded by any institution. In order to meet this demand, Grid computing has been considered as one of the most important fields of research. One of the important issues in grid environment is reliability in Grid service which must be studied. The study of Grid service helps systems’ designers to create better systems with more reliability. Also, it helps the users to use Grid environment logically. The main purpose of Grid system is preparing services with high reliability and the least cost for many users as well as supporting collaborative jobs. On one hand, resources have important role in increasing and decreasing Grid application. If resources are limited, defilewii be the result; therefore, will decrease Gird efficiency will decrease. In this paper, swarm intelligence Algorithm has been applied for Grid load balance. Since Gird environment is dynamic, we use glowworm algorithm in sites in order to balance the load. The algorithm simulation results presented by MATLAB software showed that this algorithm can increase efficiency as well as Grid environment reliability.