The invention provides a data transmission method and device, wherein the method comprises the steps of: obtaining a random integer r, carrying out operation on all integers in the interval [r, r+N-1] successively with the number N of data to be transmitted, and generating N new sequence identifiers corresponding to the data to be transmitted; and transmitting the data to be transmitted in sequence according to the generation sequence of the new sequence identifiers. By adopting the method and the device, the attack resistance of data transmission is effectively improved, and the information leakage risk is lowered.