I modified a file in IntelliJ IDEA that modification not saved on that day since I lost that changes I try to get back that code but its doesn't show any changes on that day and time how to solve this?
What you describe is a very unusual situation; one I've never heard of happening in my 12 years of using IDEA. IntelliJ IDEA automatically saves files at critical times, including closing the program. The only thing that would prevent it from saving a file is if there were permission issues with the directory containing the file. But even then, it should warn you that the file is read only and cannot be saved.
If the problem continues to occur, try uninstalling and reinstalling IntelliJ IDEA. Other than that, make absolutely sure you are editing the file you think you are editing. Perhaps there is a configuration problem.