Objectives The purpose of this study is to analyze the effect of test-wiseness (TW) strategy on elementary school students' science academic achievement according to the type of test instrument. Methods In this study, the data were collected by conducting the TW level test, science academic achievement test divided into supply type and selection type for 94 elementary school students in Gyeongsangnam-do, and their relevance and statistical significance were analyzed through one-way ANOVA and post-test. Results First, elementary school students were using the TW strategy in the order of TW_After, TW_Before, and TW_While. Second, a statistically significant correlation was found in the relationship between the TW strategy level of elementary school students and the academic achievement level of the supply type test. Third, elementary school students with high science academic achievement levels were more actively applying the TW strategy to the test than students of other levels. Conclusions The TW strategy of elementary school students is a factor that has a significant effect on the science achievement level and the results of the supply type academic achievement, so it is necessary to consider the factors for the TW strategy in the field of science education test in the future.