The invention discloses a private parking space sharing method and a parking space lock. The method includes the steps that firstly, a parking space using request from a user is received; secondly, the user is guided to enter the advance payment procedure of the parking space using charge according to the parking space using request; thirdly, whether advance payment of the parking space using charge is completed or not is monitored, if yes, the fourth step is executed, and if not, monitoring is conducted continuously; fourthly, the parking space lock is controlled to be unlocked for parking, and meanwhile parking timing is started; fifthly, whether a vehicle on a parking space runs away or not is judged, if not, time is kept continuously, and if yes, the sixth step is executed; sixthly, time keeping is stopped, the charge corresponding to the parking duration is deducted from the parking space using charge which is paid in advance, and meanwhile the parking space lock is controlled to reset and parking is forbidden.