The public scientific literacy is related with the comprehensive quality and the creativity of the talents and the comprehensive competitive power of a country. The survey of the public scientific literacy may serve as an important reference for the policy-making and assessment. It was conducted eight times in our country. This paper analyzes the changes of citizens' scientific literacy, makes comparisons among different groups and the changes of public cognition of scientific and technological information based on the data obtained in surveys of the years 2001, 2003, 2007 and 2010. An improvement of the public scientific literacy is seen on the whole, with a small increase of science understanding and a decrease of superstition dependence year by year. An analysis of the differences in population groups about the public scientific literacy shows that the age of people with the basic scientific literacy becomes younger in average and the male have higher proportion than the female, the people with higher education tend to have higher standard, more than half of the people with the basic scientific literacy are in the east region, the middle region takes the second place and the west region takes the last place. Besides the formal education, the television and the press are the main channels for people to obtain science and technological information. Public interest focuses on culture and education. Teachers, scientists and doctors tend to have a high cognitive level on science and technology.