Abstract: In the process of developing and designing new household appliances, the interface design has to go through many discussions and reviews from "design draft" to "sample presentation". With more and more attention paid to user experience, it is necessary to consider the subjective feelings of users reading interface information. However, the design reference specification for character size for kitchen appliance products has not been established yet, and the differences in age, vision, etc. among designers, developers and review experts should not be neglected, thus, there always exist many controversies in the design for character size during the process of product design and development. Considering the different usage scenarios of common household appliances in the kitchen and the relevant elements of interface design, the usability testing scheme of different character sizes was studied, and based on the test results, it provided a reference for the design of character size in enterprise interface design.

Key words: User experience, Character size, Usability testing, Kitchen appliances, Interface design