How many time from the border (HGKG) to the Shenzhen Bao'an International Airport with Taxi?

Well, the duration cannot be estimated exactly because the time of passing the custom is not sure.
So you need to prepare 2.5 to 3.5 hours about this transfer. The fare is 900 to 1,000 HKD in general.

Or you can take the direct ferry at the HK Airport and get off at the destination. The schedules are 11:20, 14:45 and 17:30. The duration is just around 45 mins. The ticket fare is 295 HKD per person.