Disclosed is a chip. The chip comprises a substrate (1) and a base layer (2) in pressing arrangement with the substrate; the substrate comprises a first surface (1a) and a second surface (1b) in opposite arrangement, reaction tank arrays formed by a plurality of flowing channels (11) are arranged on the first surface of the substrate at intervals, two oppositely arranged side walls (111, 112) of each flowing channel (11) stretch along the length direction of the flowing channel (11) and intersect at two ends of the flowing channel to form two tapered tail ends (113) with included angles, and a fluid inlet hole (12) and a fluid outlet hole (13) which are communicated with the second surface of the substrate are respectively provided on the surfaces of the two tapered tail ends (113); and the base layer (2) comprises a transparent base (21) and a spacing layer (22) arranged on the surface of the transparent base, the spacing layer (22) is in contact with the firs surface (1a) of the substrate, and a corrosion groove is provided on the spacing layer (22) corresponding to a position where the flowing channel (11) is located. The flow field distribution of the chip is good, the deformation rate of a base in the chip is low, and the fluid in the chip can be fully flushed or replaced. Also disclosed is an application of the chip.