Indication information sending method, and data sending method and device

The embodiments of the invention provide an indication information sending method, and a data sending method and device. The indication information sending method comprises: starting monitoring a channel from a time slot initial time, if it is monitored that the time slot channel is idle from the time slot initial time to a preset time point, determining that a time slot is idle, and sending time slot idle indication information to at least one site at the preset time point so as to enable a site with data to be sent to use the channel within the residual time of the time slot according to the time slot idle indication information. According to the embodiments of the invention, a channel is monitored from a time slot initial time, and if the time slot channel is idle, time slot idle indication information is sent to a site so as to enable a site with data to be sent to use the channel within the residual time of a time slot according to the time slot idle indication information such that the channel utilization rate and the real time performance of the site in data reporting are improved.