While no one would deny the fact that translated science textbooks may facilitate students’ acquisition of scientific knowledge, many current scientific textbook translations are difficult to comprehend from the student’s perspective. Whether the difficulty is caused by the method of translation is not known. The major purpose of this research, therefore, is to study the effects of different methods of translating English scientific textbook into Chinese on the comprehension of college students. The research was conducted via the following steps. First, four typical Chinese scientific articles from a popular textbook translated from English were selected as the original target texts, and a re-translation of the same four articles applying Nida’s notion of dynamic equivalence and Newmark’s communicative approach was taken as the modified target texts. Then, multiple-choice tests based on these two types of translation texts were designed to gauge reading comprehension. Two randomly selected groups of engineering students were asked to take these tests after respectively reading the two types of target texts, and the results of the tests were analyzed using a t-test. The analysis showed that the differences between the two groups were significant and that the students reading the modified target texts had better comprehension than those reading the original target texts. It can be concluded that the method of translation does affect readers’ comprehension level and that modified translation tends to be more comprehensible. By applying methods from translation theories, the modified translations became significantly more comprehensible to the readers, which suggests that Nida’s dynamic equivalence and Newmark’s communicative approach can have practical applications to scientific textbook translation. Moreover, interviews with students also indicated that word-for-word translation tends to cause more misunderstandings, and long sentence constructions are apt to create confusion.