This study addresses a fabrication process of PDA bead temperature sensor using microfluidic technique and characteristic analysis of the sensor. We synthesized liquid diacetylene monomer, methyl pentacosa-10,12-diynoate(PCDA-Me), and prepared PDA supramolecules displayed a sharp blue-to-red colorimetric transition. Entire fabrication process of PDA bead sensor consists of microdroplet generation, crystallization, and activation. Microdroplet is easily fabricated by sheathing effect and its size can be controlled by variation of flow rate ratio between core and sheath flow. After PCDA-Me droplets are collected into a reservoir (filled with aqueous solution), they are crystallized at about 0℃, and then, activated by 254 nm UV exposure showing blue color. To evaluate a sensing performance of the PDA microdroplet, we apply temperature changes to the microdroplet and analyze red fluorescence emitted from PDA microdroplet.