Provided is a microfluidic chip having an inlet/outlet structure optimized for sealing an inlet/outlet of a microfluidic chip using a UV curable sealing material, a microfluidic chip having the inlet/outlet structure, and a method of sealing the inlet/outlet of the microfluidic chip using a UV curable sealing material. It is possible to provide a semi-permanent seal with less contamination from a fluid sample or a harmful reagent, and the inlet/outlet of the microfluidic chip can be firmly sealed using simple equipment and without high-temperature/high-pressure conditions. By using the inlet/outlet structure of the microfluidic chip and the sealing method thereof, it is possible not only to improve the accuracy and deviation of the reaction result as the generation of bubbles is suppressed even when a predetermined reaction is performed on the microfluidic chip, but also it is possible to apply a fully automated system by eliminating the need for ancillary equipment such as a chip case and minimizing or eliminating manual operations.