Exploring people’s attitudes toward the appearance design of social robots in a low-cost and efficient way, and enhancing the experience of human–robot interaction have always been topics of concern for robot developers and interaction designers. This study aimed to explore the influence of the baby schema effect on users’ perceptions of cuteness and trustworthiness pertinent to social robot faces through two experiments. Experiment 1 used 100 uniformly processed pictures of robot faces in the real world to help explore the linear relationship among the degree of baby face, cuteness, and trustworthiness, and received a total of 98 valid questionnaires via the Internet. Experiment 2 was a 5 × 3 within-subjects factorial design. The research variables were robot type (i.e. MAKI, RoboThespian, Flobi, Pepper, and iCat) and baby schema (low schema, uncontrolled, and high schema); their impact on users’ perceptions of cuteness and trustworthiness was investigated. A total of 175 valid questionnaires were collected via the Internet. The generated results are as follows: (1) The degree of baby face and perceived emotion of social robot faces had a positive impact on trustworthiness for most real-world robots. (2) This study obtained the correlation formula of baby face, cuteness, and trustworthiness from a quantitative point of view, thus providing a reference for research on the related credibility of communication robots. (3) In general, baby schema effect also existed in the cuteness evaluation of most real-world robots. Faces with high schema were considered cuter and more trustworthy than uncontrolled or low schema faces. (4) Robot type and baby schema had a significant interaction with cuteness and trustworthiness. (5) However, for certain types of robots, baby schema effect may also have a counter-effect, that is, an overly high baby schema may reduce users’ perceptions of the cuteness and trustworthiness of social robots.