I am a Chinese citizen. I overstayed my previous Spanish visa for 6 months (for personal reasons). Now I am back in China. I also did not face any problems while exit and was also not charged any overstay fee. And after 1 month I am re-applying for Schengen visa. Will my visa be rejected?
Ultimately, we cannot tell whether your visa will be rejected. Also, IANAL. However, note that:
There is a passport check when exiting the Schengen area. If they told you that you are banned from re-entry, then....so is it. You didn't write that happened when exiting the Schengen area, so we don't really know. If you were not fined when leaving the Schengen area, your chances may be better as your application may not be automatically rejected.
If you plan on re-applying, you should be able to provide verifiable evidence that you will not overstay again. After an overstay, the consular officer will find it likely that you will do it again, unless you can convince them otherwise. So unless you can provide such evidence, you may want to save the application fee.