Fonts in rhel7 are ugly (The post now with screenshots)

I'm using visual studio code for develop in rhel7 with the default settings.
But I've found the fonts are ugly compare with the fonts in gedit and terminal.
Here is my screenshot, how to fix this problem?
I also found this is no same problem in fedora 27.
Could any body help me?

In the vscode fonts are NOT anti-aliased

In the system provide application fonts are anti-aliased