China's green card (permanent residence) can be obtained through family reunion: your spouse is a Chinese citizen or holds permanent residence, the marriage has lasted at least 5 years, and you have lived in China continuously for 5 years, staying at least 9 months each year. Children under 18 may follow.
The application requires many documents: marriage certificate (translated and notarized), medical report, certificate of no criminal record, proof of income and housing, and more. Translate everything into Chinese, notarize, and submit to the local Exit-Entry Administration Bureau.
Approval usually takes 6 months to a year. The green card is valid for 5 or 10 years and can be renewed. Once you have it, entering and leaving China no longer needs a visa — very convenient.