It used to but it doesn't anymore.
The first 3 seasons and the first two book + part 1 of the third line up almost perfectly.
Season 4 is still kinda the second half of the third book.
After that no.
It's a mix and match of the 4th book, 5th book, their own material perhaps based on Martins hints and maybe of the 6th book which we wont know until 2020 or later since that's when it'll be out. Maybe (yeah official date is sooner but every time we get close to it it's moved up by a year so).
Season 7 and 8 will be a small part of the 4th and 5th books (for example the whole fake Targeryan), whatever Martin told them, whatever they made up and whatever spoilers for the last two books they have.
How much Book 7 will match anything is a stupid question for now. Try asking in 2035.