The invention discloses an uplink data sending method, an uplink data sending device and an uplink data sending system, wherein the uplink data sending method comprises the following steps: according to the request information sent by a limited mobile terminal limited by uplink transmission, sending back response message used for indicating the limited mobile terminal to perform uplink transmission to the limited mobile terminal, and sending assistance request to an assistance mobile terminal being in an idle state in a service area; after receiving confirmed assistance information returned by the assistance mobile terminal and the uplink data sent by the limited mobile terminal according to the response message, allocating the uplink data resource, indicating the limited mobile terminal to send data on the first resource, indicating the assistance mobile terminal to capture data on the first resource, and transmitting the data by utilizing a second resource; combining the data received from the first resource and the second resource after demodulation to acquire uplink data after signal strength reinforces. According to the uplink data sending method, the uplink data sending device and the uplink data sending system, the SINR (Signal-to-Interference and Noise Ratio) of receiving uplink data by a base station and the accuracy of demodulating the uplink data can be improved, and the effect of the base station uplink cover is strengthened.