A Capillary Pumped Loop is a sort of "two-phase heat transport device". In this study, the micro capillary pumped loop (MCPL) and temperature sensors embedded in the micro-channels were fabricated using MEMS technology. An open type of MCPL was applied to determine the thermal analysis of MCPL corresponding to different injection volume flow rates under the condition of constant heating power 20W. A series of experiments yielded numerous results and are as follows: first, a larger injection volume flow rate results in a lower system temperature. Second, the thermal bubbles begin to degenerate into smaller bubbles at Q volume = 2 μl/min. In addition, the phenomenon of slug flow is observed with increasing injection volume flow rates, especially for the case of Q volume = 15 μl/min. Although the temperature of MCPL was reduced with the injection volume rate, the MCPL possessed an almost constant temperature difference regardless of injection volume flow rate. These findings will be useful in determining the optimal design of MCPL.