First notebook entry: Introducing myself

I am a Chinese,i live in GUIYANG city now. I used to be an electric power engineer in a powerplant that is in the mountains far away from my home.For some reason I resigned a few years ago.
I want to practice my English to a very fluent level,then I can teach my son,maybe I will do some jobs related to English in the future.

This was well written, you were only missing a few small particles and prepositions.

Note: When you say "for some reason I resigned a few years ago" this is grammatically correct but it makes it seem like you don't know or can't remember why you resigned. Maybe that's true!  Generally though in English, if someone is someone is telling you they resigned without wanting to go into detail, they would say "for several reasons I resigned a few years ago".

"For some reason" is often used in English as a phrase that has a similar meaning to "I don't know why".