A reliable data transmission method and system based on a predicted amount of data in a vehicle-to-infrastructure (V2I) network is disclosed. A data transmission method of a base station includes determining a maximum amount of data to be transmitted from the base station disposed around a road to a vehicle traveling on the road, determining an encoding number for systematic network coding (SNC) based on the determined amount of data, performing the SNC on original data based on the encoding number and the amount of data, and transmitting encoded data obtained by performing the SNC to the vehicle.