Fuente: Wipo "IOT" The invention relates to the field of communication, in particular to a data transmission method of an NB-IOT end, an NB-IOT chip, NB-IOT equipment, a NB-IOT communication system and a computer readable storage medium. The method comprises: when the NRSRP and the SINR measured by the NB-IOT end meet a preset condition, the NB-IOT end determines corrected NRSRP according to the SINR measured by the NB-IOT end and the NRSRP measured by the NB-IOT end, and the NB-IOT end determines ECL according to the corrected NRSRP; and the NB-IOT end sends a random access preamble to a base station through the NPRACH in a configuration corresponding to the ECL for the NB-IOT end to establish a connection with the base station. When the NRSRP and the SINR measured by the NB-IOT end meet the preset condition, the ECL is determined through the corrected NRSRP. The problem of long data transmission time consumption caused by improper ECL configuration is solved, and the user experience is improved.