How can I do ADB backup without PC? I can backup with PC by "adb backup"command.
 But can I create backup file without using a PC somehow? 
Android device standalone.
Yes you can. There are some tools to provide you with this functionality, e.g. Helium - App Sync and Backup. If your device is rooted, this app should work out-of-the-box. Otherwise you will need to initialize it once after each device start (reboot), which then requires a PC with ADB.



As requested in the comments, a few hints on how to get Helium started on a non-rooted device. First, this requires you to have at least a basic setup of ADB done on your computer (see: Is there a minimal installation of ADB?). Having met that, it should be as easy as enabling USB-Debugging on your Android device, connecting it via USB to the PC, and run the helper script downloaded from Helum's web page. The last 3 steps have to be repeated only once after each reboot of the device, and activate a background process Helium itself requires but cannot start itself (the user via ADB has higher privileges than an app in user-space, and thus can).