Abstract :
This research is aimed to know the ability of fourth semester students to use prefix and suffix in English. English Affixes is one of the important aspect in vocabulary building because the students can know how to create new word and students can also add knowledge about the meaning of each word in the form of prefixes and suffixes. The design of the research is a descriptive research. The Sources of data obtained from 30 students of the fourth semester class of 2018/2019 FKIP ISLAMIC UNIVERSITY OF RIAU by using random sampling techniques. Researchers used a test called The Word Part Level Test (WPLT), which consists of three categories, namely in terms of form, meaning and use. The test used by researchers is in the form of multiple choice and fill the blank. The results of data analysis from this study indicate that the percentage of students' score ability with Excellent level is 27%, Good level ability is 53%, Fair level ability is 6%, then Poor level ability is 7%, and Very Poor level ability is 7 %. So it can be concluded that the ability of fourth semester students in using English affixes is classified as Good with a percentage of 53%.