本研究採用穆林發展測驗（Mullen Scale of Early Learning, MSEL），評估40名生理年齡3歲以下自閉症類幼兒，控制組為發展遲緩幼兒及一般發展嬰兒。研究目的為：第一、評估自閉症類幼兒，認知能力的優弱勢處；第二由MSEL的表現，嘗試找出可以協助篩檢自閉症類幼兒的參考指標；第三、再次檢驗MSEL能力表現和自閉症症狀的相關性。結果：（1）自閉症類幼兒認知能力的弱勢處為語言能力，精細動作為相對優勢能力；（2）自閉症幼兒及整體發展遲緩幼兒，能力表現型態存在差異，但依據能力表現區辨自閉症與否需要謹慎。（3）探討自閉症症狀和認知能力的相關性，需要區分次類型；選擇認知能力的指標宜採用發展商數，而非年齡當量。本研究結果指出自閉症類幼兒認知能力的優弱勢處，可以提供早期療育與早期篩檢的思考方向。 The present study examined the cognitive strengths and weaknesses of young children with autism spectrum disorder (ASD), explored the relationship between cognitive abilities (as measured by the Mullen Scale of Early Learning; MSEL) and the symptomatology of autism, and sought to uncover the indicators for differentiating young children with ASD from those with developmental delay (DD). The ASD group consisted of 40 young children with ASD who were under 3 years of age, and the control groups consisted of young children with DD and normal developing children. Results showed that young children with ASD demonstrated poorer performance on language ability and better performance on fine motor skills. The profiles of MSEL revealed differences between children with autism and those with overall developmental delay. However, screening for autism based on the profiles of MSEL should be cautioned. Additionally, the use of ASD subtypes was required to understand the relationship between the cognitive abilities of MSEL and autistic symptoms. The results also suggested that the development quotient from MSEL would be a better cognitive indicator than age equivalence. The authors provide a developmental pattern of cognitive abilities in young children with ASD, and discuss implications for early screening and early intervention.