通过简单的搜索就很容易找到它。

在您的index.php中添加以下3行。

/*
|--------------------------------------------------------------------------
| Turn On The Lights
|--------------------------------------------------------------------------
|
| We need to illuminate PHP development, so let us turn on the lights.
| This bootstraps the framework and gets it ready for use, then it
| will load up this application so that we can run it and send
| the responses back to the browser and delight our users.
|
*/

$app = require_once __DIR__.'/../bootstrap/app.php';

// set the public path to this directory
$app->bind('path.public', function() {
    return __DIR__;
});

编辑：

正如Burak Erdem提到的，另一个选择（也是更可取的）是将其放入\App\Providers\AppServiceProvider
register()方法中。

/**
 * Register any application services.
 *
 * @return void
 */
public function register()
{
    // ...

    $this->app->bind('path.public', function() {
        return base_path('public_html');
    });
}