默认下载的Flash插件安装或更新都是在线安装的，通常在国内的速度都是非常慢的，后来google到了离线版的Flash插件安装包。中间的{$main.versio}是主版本号，比如13、14等，目前最新版本为17。
Windows系统
IE: http://download.macromedia.com/get/flashplayer/current/licensing/win/install_flash_player_{$main.version}_active_x.exe
Firefox或Google Chrome：http://download.macromedia.com/get/flashplayer/current/licensing/win/install_flash_player_{$main.version}_plugin.exe
Mac系统
http://fpdownload.macromedia.com/get/flashplayer/current/licensing/mac/install_flash_player_{$main.version}_osx.dmg
比如windows下v17版本针对非IE的Flash插件下载地址为：http://download.macromedia.com/get/flashplayer/current/licensing/win/install_flash_player_17_plugin.exe
参考资料：
Where can I find the "Extended Support Release" of Flash Player for Windows or Macintosh?