hello, can you please advice, how much a taxi will charge from beijing airport to dongying??

For Dongying, do you refer to the Dongying City in Shandong Province?
If so, I do not think there is taxi taking you from the airport to reach that city. There is about 420km between the two places.
From BJ, you can go to Bawangfeng Long-distance Bus Station to take bus to reach Dongying directly in about four to five hours. The bus fare is around 151RMB to 171RMB.
From the airport to Bawangfen Bus Station, you can take the airport shuttle bus line 1 to reach Dabeiyao (Guomaoqiao) Station and then change to take a taxi to reach the bus station.