I recently got 1,075 rep and now I only have 637, Reputation log told me that I lost 704 rep on February 17, ironically I didn't earn 704 rep on February 17, What is the problem?
The vote fraud script doesn't work on serial voting patterns immediately. Serial upvoting (and likewise serial downvoting) tends to happen over a period of a couple of days before it gets reversed.
There's at least one case of possible serial upvoting on February 16 with a looooooong line of upvotes that all occurred in the span of 5 minutes, accounting for about 200 reputation. I'm not sure where the other 500-ish rep came from, as there doesn't appear to have been any other suspicious voting activity logged in your reputation history since you joined the site. The days on which you went beyond 200 daily reputation had bounty and association bonus activities, so I would rule those out.
The problem seems to be the fact that there are a small number of users that have artificially inflated your reputation.
Looking further into those users that inflated your reputation, it would seem that your account, as well as the accounts of those users, are very, very specifically tied to each other, and not tied to any other accounts in the same way.
In other words, you have some socks that you were using to artificially inflate your reputation, or you have people you are colluding with in a vote ring.