Individuals diagnosed with autism are often thought to face challenges in comprehensive metaphors, even for the individuals without intellectual impairment. This study is to investigate the features and mechanisms of metaphor integration in the process of metaphor comprehension in real-time and context-free situations in autism, as well as the influence of the mental complexity of metaphor. Twenty autistic adults and twenty typically developing peers carried out a Lexical Decision Task and a Recognition Task. The results of the study showed that, there are deficiencies in real-time metaphor comprehension in autistic adults without intellectual impairment. It may caused by their relatively inefficient integration of metaphor semantics. This mechanism was equally pronounced in the metaphors with different mental complexity.