hi. how much it will cost from beijing capital airport to Liuliqiao Long-Distance Bus Station?

The taxi fare is around 130 to 150RMB for a single trip.
Or you can take the airport shuttle bus line 4 to reach Gongzhufen Bus Station and then change a taxi to that bus station. There is around 4km between the Gongzhufen and the Liuliqiao Bus Station, so in this way, the taxi fare will be much cheaper.