An uplink grant-free transmission method in Ultra Reliable & Low Latency Communication, URLLC, performed by a terminal side device, comprising: receiving a configuration parameter, the configuration parameter comprising first information indicating a correspondence between time-domain resources for URLLC uplink transmission and identifiers of Hybrid Automatic Repeat reQuest, HARQ, processes; and transmitting (S 102), after the arrival of a URLLC service, data for the URLLC service using a corresponding HARQ process on an available time-domain resource for the URLLC uplink transmission, wherein the transmitting data for the URLLC service using the corresponding HARQ process on the available time-domain resource for the URLLC uplink transmission after the arrival of the URLLC service comprises: transmitting, after the arrival of the URLLC service, the data for a first Transport Block, TB, using the first HARQ process corresponding to the first time-domain resource for the URLLC uplink transmission on the latest available first time-domain resource for the URLLC uplink transmission, wherein the first TB belongs to the data for the URLCC service, and the data transmitted using the first HARQ process further carries third information indicating whether the first HARQ process through which the data for the URLLC service has been transmitted and an adjacent second HARQ process subsequent to the first HARQ process are used to transmit the data for the same TB; and wherein the configuration parameter further comprises second information indicating the quantity of transmission times. receiving a configuration parameter, the configuration parameter comprising first information indicating a correspondence between time-domain resources for URLLC uplink transmission and identifiers of Hybrid Automatic Repeat reQuest, HARQ, processes; and transmitting (S 102), after the arrival of a URLLC service, data for the URLLC service using a corresponding HARQ process on an available time-domain resource for the URLLC uplink transmission, wherein the transmitting data for the URLLC service using the corresponding HARQ process on the available time-domain resource for the URLLC uplink transmission after the arrival of the URLLC service comprises: transmitting, after the arrival of the URLLC service, the data for a first Transport Block, TB, using the first HARQ process corresponding to the first time-domain resource for the URLLC uplink transmission on the latest available first time-domain resource for the URLLC uplink transmission, wherein the first TB belongs to the data for the URLCC service, and the data transmitted using the first HARQ process further carries third information indicating whether the first HARQ process through which the data for the URLLC service has been transmitted and an adjacent second HARQ process subsequent to the first HARQ process are used to transmit the data for the same TB; and wherein the configuration parameter further comprises second information indicating the quantity of transmission times. transmitting, after the arrival of the URLLC service, the data for a first Transport Block, TB, using the first HARQ process corresponding to the first time-domain resource for the URLLC uplink transmission on the latest available first time-domain resource for the URLLC uplink transmission, wherein the first TB belongs to the data for the URLCC service, and the data transmitted using the first HARQ process further carries third information indicating whether the first HARQ process through which the data for the URLLC service has been transmitted and an adjacent second HARQ process subsequent to the first HARQ process are used to transmit the data for the same TB; and wherein the configuration parameter further comprises second information indicating the quantity of transmission times.