Graffiti is known as a subject of the street art, although there is difference between graffiti which is originated from essence of protest and street painting. Unlike graffiti, street painting is legal and even ordered by city authorities. Generally street painting includes subjects that are compatible to social and economic policies and even confirm them. It should be said that in this respect it is a kind of conservative art. Because of the using of wall as its medium and it today's emergence around 70s graffiti is considered as a postmodern phenomena which is accessible to public on one hand and its control is impossible on the other hand. The importance of such an uncontrollability is that everyone can uses it and in some cases this causes the antagonism of art experts and even people and in the other cases is confirmed by them. So there are a lot of different views about graffiti. Some people see it as a kind of art which uses the wall as an artistic medium. Some others believe that it's a medium used by deprived groups of society, mostly connected to the subculture young people to transmitting socio-politics devices or a form of advertisement while the rest believe that it's a vandalism activity. The lack of attention to different aspect and approaches of graffiti has cost a wide disagreement. In this essay we are going to prove that some of the graffiti works like many other art works contain social and moral expression and therefore graffiti in this respect is kind of art. Some graffiti works are created as a protesting movement in order to use art to transmit their message. There is also another aspect of graffiti which is use by street gangs to mark their territory. This aspect has neither relation to the art world nor has the content of second approach. Thus sometimes the separation of these approaches is difficult although it can be said that the graffiti ranges from the street gangs activities to art work.