I'm applying for my parents

Green card holders can not apply for parents. You have to wait until you become a citizen. Then you file I130 and I485 if your dad is in US, or file I130 and packet 3 if your dad is in China. In either case, your dad's case will be current, meaning he will not be subject to yearly quota. But the filing and process time can still be quite long. Check the USCIS website. There are detailed information there about qualification and what documentation to file.