My MacBook restart itself once a day, randomly

You have experienced a kernel panic. Kernel panics are usually, but not always, a hardware problem. In your case, you say this does not happen frequently. Do you remember what software you were using when the panic does occur? You could post one or two recent kernel panic logs. Kernel panics are indicative of possible hardware failure, so you should Check your Mac with hardware diagnostics or AHT. Kernel panic logs are found in: /Library/Logs/DiagnosticReports/ folder.

The only way to save your files is if the computer can be used long enough for you to backup. If you cannot backup, then your data will be lost because recovery is a destructive process. You can try booting into Safe Mode which might prevent the recurrence of the panic:

Boot Into Safe Mode

1. If your Mac isn’t already shut down, then shut it down and wait at least 30 seconds before rebooting.
2. Immediately, at or before the chime, press and hold down the SHIFT key. 
3. Release the key after the Apple logo and progress bar appear.
4. Safe mode startup is much slower than normal startup, so be patient.
5. When the Login Screen appears enter your admin password. If you use automatic login, then this means you are in safe mode.

If you are able to do an erase and install, then please provide me with the exact MBP model you have. To find the complete model information select About This Mac from the Apple menu. You can create a snapshot of the dialog as follows:

How to take a screenshot on your Mac

Capture, Save or Record Screenshots in Mac OS X - Help Desk Geek

OS X Screen Capture Shortcuts

(⌘⬆︎3) Command-Shift-3 Capture the screen to a file

(⌘⬆︎⌃3) Command-Shift-Control-3 Capture the screen to the Clipboard

(⌘⬆︎4) Command-Shift-4 Capture a selection to a file

(⌘⬆︎⌃4) Command-Shift-Control-4 Capture a selection to the Clipboard

(⌘⬆︎5) Command-Shift-5 Invoke new screen grabber

You can then post the image in the forum's message editor.

Sorry, but I have no idea how to interpret that log. Kernel panic logs are in: /Library/Logs/DiagnosticReports/ folder. Also, here is more information related to kernel panics.

Dealing with Kernel Panics

Disconnect any third-party peripherals including any USB hubs. How to use safe mode on your Mac, Use safe mode to isolate issues with your Mac - Apple Support then boot the computer into Safe Mode: Use safe mode to isolate issues with your Mac - Apple Support and Playing Safe- what does Safe mode do? See Diagnosing problems- crash, freeze, panic, or spinning beach ball?, Don’t Panic! Understanding & Troubleshooting Kernel Panics in macOS, How to fix kernel panics after installing OS X updates | MacIssues, and If your Mac restarted because of a problem - Apple Support.

Kernel panics are indicative of possible hardware failure, so you should Check your Mac with hardware diagnostics or AHT. Kernel panic logs are found in: /Library/Logs/DiagnosticReports/ folder.

If you have no success figuring what is happening then you may need to examine the software you have running when the panics occur. Be sure it’s all current. If you must to resolve the problem erase the disk and reinstall macOS. Follow this outline to reset the computer to the factory-new state: Factory reset of your Mac - Apple Support.

Boot Into Safe Mode

1. If your Mac isn’t already shut down, then shut it down and wait at least 30 seconds before rebooting.
2. Immediately, at or before the chime, press and hold down the SHIFT key. 
3. Release the key after the Apple logo and progress bar appear.
4. Safe mode startup is much slower than normal startup, so be patient.
5. When the Login Screen appears enter your admin password. If you use automatic login, then this means you are in safe mode.

Post the panic log here using the Additional Text button in the message editor's toolbar as seen below. It's the third button from the right (excluding the circled "?".)

If there are no panic logs in that folder, then the panic occurred so early that it could not be logged. That sort of panic event almost always means hardware failure.