There is no item in `Login Items`, but why I boot my Mac, there still has a few software launch automatically? There is no item in Login Items, but why I boot  my Mac, there still has a few software launch automatically?
There are a group of special files that manage the opening and running of programs at launch and in the background. These files are known as Launch Agents and Daemons. Often times, third party software makes system  modifications that installs these files as a part of the software package. The software doesn't always appear in the "Login Items" list. Additionally, the "login items" list doesn't actually disable automatic launching of programs but just gives you the option to hide it. 

Without knowing the specific software, the best way to solve your issue is to look within the software's preferences. Often times, there is an option available to disable "Automatically open at Login," or something similar.  

If you cannot find an option within the program, then look to the developers website for possible instructions. Or, simply googling the issue - "how to disable [name of software] from automatic launching" will provide you with a solution. 

Alternatively, you can manually disable launch agents and daemons by changing the keys within them, but I don't recommend doing this. As I said, most software provides you with the option.

There are a few programs that scan your system and show you which launch items are actually enabled and running. Etrecheck is a great example that I recommend downloading and running.