The input method industry, long dominated by Sogou, Baidu, and iFlytek, is facing disruption as Doubao and Qwen enter the market, pushing it into the AI Native era. WeChat launched its own input method at the end of 2022, loosening the solidified market pattern with its "Tencent Ecosystem + Privacy Protection" narrative. The article divides input methods into three generations: 1.0 Tool Era (Microsoft Pinyin, early Sogou) focused on "being able to type"; 2.0 Traffic/Ecosystem Era (Sogou, Baidu, WeChat) where input methods became advertising carriers and super App connectors; and 3.0 AI Native Era, where AI manufacturers like Qianwen and Doubao treat input methods as "infrastructure" for their AI strategy rather than independent products. While these AI entrants will take market share, their core goal is securing user entry points for their AI ecosystems, making their competition with traditional input methods not in the same dimension. Traditional input methods solve "input efficiency," with AI as a post-positioned auxiliary function, helping users type already formed text. AI-native input methods address the short board of "expression efficiency," compensating for scattered ideas and difficulty organizing words. AI manufacturers build the input method as the "first contact point" and "intention executor" between their large models and users, where the input box becomes a dialog box and typing becomes creation or execution.