This paper mainly explores the impacts of presenting new words in semantically-related (SR) sets on vocabulary learning. 38 students from two classes of Grade 2 in Taiyuan Foreign Language School (Senior High School Section) participate in the whole process. The same vocabulary items unknown to all students are taught to them in 4 lessons. The difference between the experimental group and control group is that words are taught in SR sets in the former and in the latter words belonging to the same SR sets are taught in different lessons. Independent Samples T-test is employed to see if there would be a significant difference between the two groups' performance in the English-Chinese translation tests of those words. The result shows that there doesn't exist a significant difference between the two groups in SHT test, but in the LT test two weeks later, SU group performs significantly better than SR group. The research findings may provide some enlightenment for foreign language researchers.