Although atypical sensory processing is a core feature of autism spectrum disorder (ASD), there is considerable heterogeneity among ASD individuals in the modality and symptoms of atypical sensory processing. The present study examined visual processing of children with ASD, focusing on the complexity and orientation of visual information. Age- and -IQ-matched Korean children (14 ASD and 14 typically-developing (TD) children) received an orientation discrimination task involving static spatial gratings varied in complexity (simple versus complex) and orientation (horizontal versus vertical). The results revealed that ASD children had difficulty perceiving complex information regardless of orientation, whereas TD children had more difficulty with vertical gratings than horizontal gratings. Thus, group-level differences between ASD and TD children appeared greater when gratings were presented horizontally. Unlike ASD adult literature, however, ASD children did not show superior performance on simple gratings. Our findings on typical and atypical processing of ASD children have implications for both understanding the characteristics of ASD children and developing diagnostic tools for ASD.