The Library of Muhammadiyah Technology High School of Kebumen (Sekolah Tinggi Teknologi Muhammadiyah - STTM) Kebumen has a various books collection, such as journals, scientific books, social, language, engineering, magazines, and Al-Qur'an. However, the data processing in the STTM's library is currently using the conventional method of recording member data, book data, borrower data, return data, and payment penalty for late returning the book to a document. SLiMS is an open-source web-based library management system application licensed under the GPL (General Public License). This research is on how to design the Background and fonts of the SLiMS for STTM's library using the User Centered Design (UCD) method. The stages of this research begin with the identificate of the user needs and a pleasant and interactive design. The display design was created by using background images of the STTM Kebumen campus, with Arial fonts, cover book figures, search columns, and social media buttons. The validation of SLiMS display to design of STTM library used Usability Test. The result of the validation test with the Usability Scale System is good, which a value is 77.3%. It means that the display of SLiMS design was a successfull built like a user-friendly system with height usability.