A security processing method for a car sharing service includes: a smart terminal encrypting a second random code according to a first smart terminal encryption key, to obtain a first cyphertext, the first smart terminal encryption key having a first random code and order form information from a cloud server; the smart terminal receiving a third random code from a vehicle, the vehicle obtaining the third random code by decrypting the first cyphertext according to a first vehicle encryption key that includes the first random code and the order form information sent by the cloud server; the smart terminal subjecting the second random code and the third random code to comparative verification, to obtain an identity authentication result; the smart terminal sending, if the identity authentication result has passed, encrypted service data to the vehicle; and the vehicle decrypting the service data to execute the service data.