Purpose: To make early detection of individuals with autism spectrum disorder (ASD), caregiver-report instruments remain an efficient and adaptable option for the preliminary assessment. This study aimed to compare the psychometric properties of the Clancy Autism Behavior Scale (CABS) and Autism Behavior Checklist (ABC) as screening tools for ASD by caregivers. Methods: The data were collected from 154 pairs of children and their parents, who sought medical attention for suspected autism at Peking University Sixth Hospital. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Youden index, and area under the receiver operating characteristics curves (AUC) of the CABS and ABC were calculated and compared using recommended cut-off values from initial papers. The optimal cut-off values for CABS and ABC were determined according to the maximum Youden index. Results: The ABC performed better than the CABS in screening autistic persons. Specifically, the ABC demonstrated higher sensitivity than the CABS in identifying children with ASD, while the CABS exhibited superior specificity compared to the ABC. According to the maximum Youden index, the optimal cut-off value was determined to be 13 for CABS and 62 for ABC. Conclusion: The ABC exhibits higher sensitivity and overall performance in screening individuals with ASD compared to the CABS. The ABC is more suitable as a screening tool for caregivers in both domestic and clinical settings, while the CABS may be utilized when evaluation time or medical resources are limited due to its shorter completion time and fewer items.