This study aimed to develop a valid and reliable instrument, the Mental Images of Scientists Questionnaire (MISQ), and use the instrument to examine Chinese students' mental images of scientists' characters across school levels, regions, living settings, and gender. The final version of the MISQ consisted of four constructs: scientists' cognitive, affective, lifestyle, and job characters. The results showed that senior high school students gave higher scores for scientists' cognitive character construct than junior high and elementary school students did. Students from eastern regions, which have a more highly developed economy, gave the highest scores on cognitive and affective character constructs of scientists. Students from western regions, which have a less developed economy, had a relatively negative impression of scientists. Students' images of scientists' affective, lifestyle, and job characters were positively correlated with their interests in pursuing scientific careers. Future research to explore the relationships between students' mental images of scientists' characters and students' motivation to pursue science-related careers or to engage in scientific practices are recommended.