Graphs are widely used to present scientific information. Information presented in graphs can be classified into three kinds: explicit information, tacit information, and conclusive information. Reading information from graphs requires not only science content knowledge and understanding but also general logical reasoning. This study examined the abilities of reading various kinds of scientific information among students in different grades in China. The participants were 288 students in grades 9, 10, and 11. An instrument developed by the researchers and teachers was used to measure students' graph reading abilities. Results indicated that: (a) students' abilities of reading the three kinds of scientific information improved with grade; (b) students in different grades showed significant differences in reading all kinds of information except for the topics and special segments of the graphs for explicit information, tacit information requiring using mathematics tools, and conclusive information from comparison; and (c) as a whole, students of the same grade showed variation in their abilities of reading different kinds of information but the patterns of difference among the three kinds of information for the three grades were similar. This study has many implications for science education in China. It may help teachers understand students' thinking approaches to graphs and foster their abilities of interpreting them, and further inform future studies on how to adopt and design graphs in science textbooks. (Contains 5 tables, 2 figures, and 9 graphs.)