This study aims to obtain data about English expressions which high school students need in writing English academic papers on natural sciences,especially their abstracts. This would lead to developing teaching materials and designing courses for natural sciences in English for Specific Purposes (ESP). The author created a corpus from the English abstracts of research papers written by students at Hiroshima University High School from 2015-2022,from which he analyzed the characteristics of words and collocations.In addition,the author compared the corpus to a general corpus and one created from English textbooks to find characteristic expressions preferred by high school students in writing natural science papers. The results suggest that high school students produce different types of discourse in their science papers than they do in English for General Purposes(EGP)courses. Specifically, they primarily describe facts in science papers rather than express their opinions as they do in EGP writing. It was also suggested that high school students prefer certain expressions due to limitations in their English proficiency.