Minemonic technique is one of technique that might be used to improve student’s activeness in teaching learning process and improve student’s mastering about vocabulary. This research was aimed to explain the effectiveness of using mnemonic technique to teach vocabulary. The study was conducted through the experimental research at the fifth grade of SDIT Cahaya Bangsa Mijen, Semarang in academic year of 2019/2020. The data was gathered through try out test, pre-test, post test and documentation. The researcher used simple random sampling. V B was chosen as an experimental class and V A as a control class. The experimental class was taught using mnemonic technique and control class taught using lecturing and small group discussion. The test instrument were 20 multiple choice questions of vocabulary. T- test formula was used to analyze the data. The result was obtained through comparing the posttest’s average score between experimental and control class. The average score of experimental class was 76.88 and the average score of control class was 70.55. Meanwhile the pre- test’s average score of experimental class was 67.22 and the average score of control class was 67.03. In addition, it is proven that the independent t test result for post test that the t count is higher that t table (3.57 > 2.000). It means there is significant difference in the achievement between experimental class who were taught by using mnemonic technique and control class who were taught without mnemonic technique