In this paper, a new model of description of attitudes toward risks has been founded by researching on the observable fact that people's attitudes toward risks are different given the distinct conditions of risks. This model can be used for interpreting the fact that currently the harmful opportunism is widespread in our society. Based on the knowledge of attitudes toward risks, this paper analyzed the substance and inducing factors of opportunism. Moreover, it gave some strategic thoughts on opportunism prevention and encouragement of innovation which is a kind of risk-taking behavior.