This paper presents the design and implementation of a localization system using the Ring-Overlapping based on Comparison of Received Signal Strength Indicator (ROC-RSSI). The designed systems, consisting of 5 RF transceiver modules playing roles as 4 Reference nodes and one Target node, can be used to locating position of a moving object within a pre-defined area basing on the received signal strength RSSI. The RSSI values obtained by the Reference nodes are processed using the ROC-RSSI algorithm to determine relative position of the targeted object. In this work, the authors have utilized 6 Texas Instruments CC1120 RF - 169 MHz modules to build the prototype system. Tested results have shown that the system can offer accuracy of up to 80% to 85% within an area of 30m x 30m.This paper presents the design and implementation of a localization system using the Ring-Overlapping based on Comparison of Received Signal Strength Indicator (ROC-RSSI). The designed systems, consisting of 5 RF transceiver modules playing roles as 4 Reference nodes and one Target node, can be used to locating position of a moving object within a pre-defined area basing on the received signal strength RSSI. The RSSI values obtained by the Reference nodes are processed using the ROC-RSSI algorithm to determine relative position of the targeted object. In this work, the authors have utilized 6 Texas Instruments CC1120 RF - 169 MHz modules to build the prototype system. Tested results have shown that the system can offer accuracy of up to 80% to 85% within an area of 30m x 30m.