Disclosed are a heterogeneous network based-simultaneous data transmission service system and method which include a transmission device for dividing data into two or more partial data, selecting first partial data corresponding to a part of the two or more partial data, and selecting second partial data corresponding to another part of the two or more partial data; a first network device for receiving the first partial data from the transmission device; a second network device for receiving the second partial data from the transmission device; and a reception device for receiving the first partial data from the first network device, receiving the second partial data from the second network device, and reconstituting the data by combining the first partial data and the second partial data.