What does the military card xk mean at the beginning?

It's a vehicle of the Air Force Xijing Hospital. Military brand xk is a vehicle of Air Force Xijing Hospital, which belongs to the category of military management. It is a license plate with registration code issued by the Ministry of Military Transportation after the vehicles applying for the license plate are inspected, checked and registered. Military brand cars are characterized by strong safety adaptability, fast driving speed and large power-to-weight ratio.