This research paper was mainly (1) to investigate the effects of English ability-grouping teaching on students' learning in a university of technology; (2) to explore the extent of the English leaning strategy use of the Strategy Inventory for Language Learning (SILL), responded by students in the target university of technology; (3) to analyze the effects of English learning strategy use on the learning achievement of the students in the target university of technology. The SILL and a teacher-made placement test were utilized as research instruments for data collection. The SPSS statistic software was used to synthesize, analyze and explain data collected through the procedure of t-test, One-way ANOVA, ANCOVA, and Pearson-product correlation. The major findings were illustrated as follows: (1) There was significant progress on all students' English learning achievement after their joining the English ability-grouping teaching; (2) The students at intermediate level performed significantly better than the other levels, basic and high-intermediate after joining the English ability-grouping teaching, according to the scores of the posttest on English proficiency; (3) The students at intermediate level also held significantly higher frequency of use, according to the responses to the SILL, than those students at the other levels, basic and high-intermediate. It was apparent evidence that there are positive effects of English learning strategy use on the learning achievement of the students in technological universities. The present study also suggested English learning strategies should be taught and guided to students for efficient learning; moreover, the English language skill index can be presented and analyzed to examine the effectiveness of the English ability-grouping teaching.