您应该这样做，
componentDidMount而
refscallback不是。像这样
componentDidMount(){ this.nameInput.focus(); }class App extends React.Component{ componentDidMount(){ this.nameInput.focus(); } render() { return( <div> <input defaultValue="Won't focus" /> <input ref={(input) => { this.nameInput = input; }} defaultValue="will focus" /> </div> ); }}ReactDOM.render(<App />, document.getElementById('app'));<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.3.1/react.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.3.1/react-dom.js"></script><div id="app"></div>
