All the text messages sent in the last three years have been deleted. How can I check the content of the short message?

Generally, it can't be found unless there is an application from the court or the public security. You can get it from the communication company. It's usually not good. How can you find it? Or you can ask a professional to repair your mobile phone and let a professional help you recover. It is possible to find it, but there is little hope. Why are you looking for a three-year SMS record? You can see if you have backed up in the cloud. If we can find it without backup, it will take some effort.