Objective:Expertise in social perception, defined as the ability to decode another person's mental states based on basic behavioral signals (Allison et al., 2000; Beauchamp et al., 2008). The Reading the Mind in the Eyes Test (RMET) is a social-perception task of theory of mind (ToM, Meinhardt-Injac et al., 2020) and used to test different clinical disorders, like autism spectrum disorders (ASD, Peñuelas-Calvo et al., 2019). RMET has been used to demonstrate gender, cultural, genetic, and personality trait influences on ToM and elucidate its neurobiological mechanisms (Adams et al., 2010). In Taiwan, there has few sensitive tools to evaluate children's social perception, thus the purpose of this study is to examine psychometric properties of child's version of RMET in Taiwan (RMET-C-TW) and cross-cultural comparisons.Participants and Methods:RMET-C (Baron-Cohen et al., 2001) was used to assess mental state/emotion recognition (Vellante et al., 2013). It consists of photographs of the eye regions of 28 faces. Participants were asked to make a choice between four words presented, choose the one that best described for feel or think. One point was given to each correctly response. RMET-C-TW was double-translation of words to ensure cultural applicability in Taiwan. This study included both a normative sample and criteria sample. The normative sample consisted of 769 (385 male, 384 female) 3 to 9 grades students from northern Taiwan. The normative sample completed both the RMET-C-TW and Chinese Vocabulary Test (CVT) in groups at their own schools, the CVT was to ensure that participants had sufficient vocabulary skills to understand the options provided in REMT-C-TW. The criteria sample were collected from 46 matched, school-aged children with ASD (age mean = 10.52, SD = 1.62; IQ = 108.39, SD = 11.75), and normally developing controls (age mean = 10.66, SD=1.68; IQ = 109.70, SD = 12.12). These two groups were administered the (1) WISC-III (2) CVT (3) RMET-C-TW and (4) ToM Test.Results:The results showed that RMET-C-TW had acceptable test-retest reliability and internal consistency (test-retest reliability = .71, Cronbach α= .40). There were significant gender and age difference in the performance of RMET-C-TW, example female, older participants performed better. Item analysis showed 93% of items in the RMET-C-TW had cross- cultural consistency in the distribution of respondents' choices. In criteria sample, the control group's RMET-C-TW scores significantly better than ASD group. Physician diagnosis (r = .49, p < .01) and high-order ToM's scores (r = .33, p < .01) were significantly associated with RMET-C-TW scores.Conclusions:RMET-C-TW has acceptable reliability and good developmental validity (age-related growth) in three to nine grades, and future can be extended to different age and clinicians to understand the development of social perception. Therefore, RMET-C-TW can be used as an initial screening and cross-cultural tool for ASD. In addition, EF is divided into cold and hot, and hot EF makes a unique contribution to ToM in ASD (Kouklari et al., 2017), thus this tool may also be used in the future to understand the association of hot EF with social perception.