Method and device for data transmission and channel measurement

Disclosed are a method and device for data transmission and channel measurement, for use in solving the problem of low spectrum utilization rate and unlicensed spectrum resources not being fully utilized when multiplexing a channel completely by means of time-division. The method comprises the following steps: on an unlicensed spectrum, a first device performs a clear channel assessment (CCA) test on a current channel and acquires the CCA test result (S11); if the CCA test result is less than a first threshold, the first device determines a transmission power level on the basis of the CCA test result (S12); and the first device employs a transmission power corresponding to the transmission power level to transmit data (S13). By employing the present invention, when the CCA test result is less than the first threshold, the transmission power corresponding to the transmission power level determined can be employed to transmit the data; therefore, multiplexing of spectrum resources is improved, and unlicensed spectrum resources of the channel is fully utilized, thus increasing system capacity.