A microarray reaction device includes a fluid container, a reaction chamber, a first channel connected with the fluid container, a second channel connected with the reaction chamber, and a valve. The valve includes a first and second support unit, respectively including a first and second penetration opening unit, extended through a first and second surface thereof. The first and second penetration opening unit is connected to a second end of the first and second channel, respectively. The second support unit includes a third penetration opening unit extended through a second surface thereof. The first and second surfaces contact each other, such that the first support unit and the second support unit are slidably disposed with each other. The microarray reaction device further includes a storing chamber connected with the third penetration opening unit, and a pump connected to the storing chamber and providing pressure to the storing chamber.