As the breadth and depth of economic reforms increase in China, growing attention is being paid to equalities in opportunities to learn science by students of various backgrounds. In early 2009, the Chinese Ministry of Education and Ministry of Science and Technology jointly sponsored a national survey of urban eighth-grade students' science literacy along with their family and school backgrounds. The present study focused on students' understanding of basic science concepts and principles (BSCP), a subset of science literacy. The sample analyzed included 3,031 students from 109 randomly selected classes/schools. Correlation analysis, one-way analysis of variance, and two-level linear regression were conducted. The results showed that having a refrigerator, internet, more books, parents purchasing books and magazines related to school work, higher father's education level, and parents' higher expectation of the education level of their child significantly predicted higher BSCP scores; having siblings at home, owning an apartment, and frequently contacting teachers about the child significantly predicted lower BSCP scores. At the school level, the results showed that being in the first-tier or key schools, having school libraries, science popularization galleries, computer labs, adequate equipment for teaching, special budget for teacher training, special budget for science equipment, and mutual trust between teachers and students significantly predicated higher BSCP scores; and having science and technology rooms, offering science and technology interest clubs, special budget for science curriculum development, and special budget for science social practice activities significantly predicted lower BSCP scores. The implications of the above findings are discussed. (Contains 8 tables.)