Objectives Sensorimotor synchronization (SMS) refers to an individual’s motor rhythm is temporally coordinated with a predictable external rhythm. Autism spectrum disorder (ASD) children have weakened SMS performance than typically developing (TD) children, which may affect their relationship with peers and caregivers, and social cognition abilities. Synchronization referent (e.g. an adult or a non-social beat) and the length of inter-stimulus interval (ISI) would influence SMS performance. Methods In this study, we adapted a tapping task to investigate the SMS ability in twenty-one 5–8-year-old high-functioning ASD and twenty-one age-, gender- and IQ-matched TD children. Children were asked to tap on a computer keyboard with videos of a woman or a robot tapping with one finger. We compared the synchronization performance of the two groups when they synchronized with different partners (an adult or an NAO robot) and under different ISIs (800 ms or 1500 ms). The relationships with participants’ autistic traits (Social Responsiveness Scale (SRS-2) and Autism Spectrum Quotient), and cognitive ability (IQ) were also examined. Results We found that ASD children had an overall attenuated synchronizing accuracy and stability than TD children only when ISI was longer than one second. Both groups performed better when synchronized with the NAO robot than the adult partner. The synchronization performance was correlated with the cognitive ability of ASD children when ISI was 1500 ms. Conclusions Results show that tapping with the robot could improve the SMS performance of ASD children since it promoted a higher motivation level. ASD children have an attenuated SMS ability, which may be caused by abnormal temporal perceptions when ISI is longer than one second, while their SMS ability may be intact in sub-second ISIs.