Abstract: A microfluidic detection unit comprises at least one fluid injection section, a fluid storage section and a detection section. Each fluid injection section defines a fluid outlet; the fluid storage section is in gas communication with the atmosphere and defines a fluid inlet; the detection section defines a first end in communication with the fluid outlet and a second end in communication with the fluid inlet. A height difference is defined between the fluid outlet and the fluid inlet along the direction of gravity. When a first fluid is injected from the at least one fluid injection section, the first fluid is driven by gravity to pass through the detection section and accumulate to form a droplet at the fluid inlet, such that a state of fluid pressure equilibrium of the first fluid is established.