Based on corporate behavioral finance theory, this paper studies the impact of textual information of management earning forecast and its language characteristics on market response. Using the data of listed company from 2012 to 2016, this paper finds that the optimism of textual information has a positive effect on stock returns. However, this effect is affected by the language features of textual information, more specifically, the market response toward textual information is weakening with the exaggeration or bias of language. This phenomenon indicates the effectiveness of the China capital market. This paper extends the research area of textual information and management earning forecast, and provides new evidences to corporate behavioral finance theory.