The present invention provides an intelligent charging system and method for use in a parking lot. The system comprises a detecting unit, an on-board unit and a corresponding means of payment. The on-board unit is disposed on a vehicle and configured to acquire a parking time parameter, derive a parking fee according to the parking time parameter and a rate parameter stored in the on-board unit, and deduct the parking fee from the means of payment. The detecting unit is configured to, through information interaction with the on-board unit, determine whether the on-board unit operates normally. The present invention can be used to reduce the investment cost and improve the monitoring management of public parking lots.