They managed to get a deal with the Soviet Union before it collapsed.
Key point: Money talks and the Soviet Union-turned-Russia really needed the cash. Of course, China has happy to get the advanced tech.
The Sukhoi Su-27 “Flanker” was never planned to exported when it was originally developed, unlike its lighter cousin, the MiG-29. However, ever since being approved for export it has been one of the most popular fighter exports in the Asian region. The first customer for the Su-27 was China, which secured a procurement deal while the Soviet Union still existed. But how did Beijing accomplish this?