Several months age I accidentally deleted all the index of my site by google webmaster tools. I guess this is the cause. Because everything in my site is legal. The content is 100% original, the robots.txt file is OK, and I have tried many tools to simulate googlebot to crawl my site, it is normal. So the only reason I can find is the accidental delete. Please tell me how to let google index my site again?
undelete the same url in webmasters tools and your site should be indexed again in few minutes by google
hmm.. it never even occurred to me that this could happen. I'm glad you posted this! Cuz I don't want it to happen to me!