The present disclosure provides a data transmission method and device, and relates to the technical field of communications. The data transmission method is applied to the data transmission device and includes: determining a transmission type used when performing data transmission, where the transmission type includes one of a single transmission of target data in one slot and multiple repetitive transmissions of target data in one slot; determining the number of repetitive transmissions of the target data in each slot, when the transmission type is multiple repetitive transmissions of target data in one slot; transmitting the target data according to the number of repetitive transmissions of the target data in each slot.