how to reach from changchun airport to beihua university?

The university is in Jilin. You can take the shuttle bus line 6 to the Main Railway Station, where you can take the bullet trains to Jilin. The duration is about 40 mins.
The university has three campuses, which one do you refer to?

If the main campus, east campus, you can take the bus from JInlin Railway Station to Zhiyebing Fangzhisuo Station. Then walk about 520 yards, you will reach the campus. Or you can take a taxi, and the fare is about CNY15.