The invention discloses a method for vehicle oil consumption statistics. According to the method, the OBD interface of an oil consumption statistic device is connected to the OBD interface of a vehicle-mounted diagnosis system so as to collect the realtime work condition data of the vehicle; according to the information such as the equivalent ratio Vlambda of a linear or broadband type oxygen sensor, the air intake flow value Vmaf of the vehicle engine, and the like, by combining the vehicle's archival information, the realtime oil consumption of the vehicle can be calculated by an instant oil consumption calculation formula, and thus the oil consumption statistics can be achieved. The OBD interface of an oil statistic device is inserted into an original OBD interface of a vehicle to collect the vehicle work condition data, the original circuit of the vehicle does not to be broken or changed, the installation is convenient, the method is practical and safe, the quality guarantee of the vehicle will not be influenced, and thus the method can be accepted by the customers more easily. The oil consumption calculated through the work condition data will not be influenced by the external environment or road condition during the driving process, the precision is high, moreover, the realtime oil consumption of the vehicle can be calculated, and the oil consumption data precise synchronous comparison and analysis can be realized.