The invention discloses a narrow band uplink sending method and device. The method comprises the steps of: at a sub-carrier interval of 3.75kHz and in an uplink single-tone mode of NB-IoT (Narrow BandInternet of Things), acquiring an uplink and downlink sub-frame proportion under a current TDD (Time Division Duplexing) system; according to the uplink and downlink sub-frame proportion, acquiring acorresponding complete NB-slot and partial NB-slot; and according to a configuration rule, determining an allocation mode of the complete NB-slot or an allocation mode of the complete NB-slot and thepartial NB-slot, which corresponds to the uplink and downlink sub-frame proportion. With respect to the time unit of NB-slot in FDD (Frequency Division Duplexing), time units of two types of NB-slotsare newly introduced, one type is the partial NB-slot, and the other type is a flexible NB-slot, so that the narrow band uplink sending method and device can be applicable to sing-tone transmission of a NPUSCH at the sub-carrier interval of 3.75kHz and cannot generate interference to a LTE (Long Term Evolution) system.