A resource request method and system, a device, and a network side node are provided. The method includes the following steps: A target device sends a first target device message to a relay device. When receiving the first target device message, the relay device sends a first relay device message to a network side node according to the first target device message. The network side node receives the first relay device message, and sends first grant information to the target device according to the first relay device message. The first grant information includes a data transmission resource allocated by the network side node to the target device. According to embodiments of the present disclosure, energy consumption of a sending device, that is, a target device, can be reduced while the sending device obtains a transmission resource.