Firstly，based on historical materials of Tang and Song dynasties，this article sorts out the concept of god Erlang （二郎神） and concludes that the belief in god Erlang was already familiar to people during Emperor Yi or Xi period of Tang dynasty at the latest. In Song dynasty，the evolution of the god Erlang in folks cultures had been established. Secondly，combining classical novels，domestic and foreign paintings，coin decorations，statutes and sculptures of porcelain，etc.，to verify the specific image of god Erlang，and further discusses his companion hound named Xiaotian （啸天） and the origin of the sitting posture Erlang，etc. related to god Erlang. Finally，a comparative study of a large number of texts and image materials found that god Erlang mixed several cultures among different regions during the process of stereotypes. In addition to Buddhism and Zoroastrian elements，its components may also be related to Taoism.