Autism Spectrum Disorder causes difficulties in interaction and communication, hence this study is an attempt to shed some light on autistic children's discourse concerning the way they employ cohesive ties and show cooperation during conversation. This is a preliminary step to propose some suggestions that may help these children with their troubles and challenging conditions. Research method is based on an analysis of the autistic discourse regarding two points: children's observance of the Cooperative Principle in conversation and their use of cohesive ties. Grice's notion of The Cooperative Principle (1975) that governs conversational behaviors assume that conversation is a cooperative endeavor between interactants. Halliday and Hasan (1976) discuss the notion of cohesion in discourse and consider that any text should be unified by certain cohesive devices. This study approaches autistic children's discourse from the two perspectives: cooperation and cohesion. It concludes that autistic children employ echolalia to implicate their acceptance of the activity presented, which is a cooperative act. It is concluded that using words relating to the same relevant topic is nearly the only cohesive device employed by autistic children. Research limitation has to do with conducting an analysis of a child's discourse despite the child's inability to communicate and his repetitive linguistic behaviors. The study may be practical in suggesting some directions to improve autistic children's performance and social communication. Echolalia, for instance, may be considered as a positive act of cooperation, and be taken as a step to move forward and train the child to repeat and utter a comment or express his desire. Autistic children should be trained to use various cohesive devices, such as synonymy and antonymy.  This paper tries to make better language activities related to autistic children.