The purpose of this paper is to check the Game Rating and Administration Committee(GRAC), established in 2013 as revision of law to the Game Industry Promotion Act, restricts the freedom of expression. Game Rating system in Korea is not formed spontaneously in the market, unlike oversea, the Government has designed public systems. The GRAC has classified only “Rating”, but it regulates the expressions of the Game and gaming industry itself by other than raising rating. In cases the GRAC issued decisions of rating rejection are suspected to be in mistake in the interpretation of relevant laws, resulting in expressions of the game is limited. The content modification notifying system has unclear criteria, and it regulates not the contents of the game but the ways of using games. It is contrary to the principle of the content centrality of rating, and Operators have to impose self-censorship when they change game contents.