Abstract: A microvalve (8), comprising a first flow guide channel (841) for communicating with microchannels (401, 402, 403, 404) in a chip and a second flow guide channel (842) for communicating liquid storage recesses (11, 12) in the chip to the ambient atmosphere, wherein the first flow guide channel and the second flow guide channel do not communicate with each other. Also provided are a microfluidic chip (100) and a method for controlling the flow of a plurality of fluids in a microfluidic chip. The microfluidic chip (100) comprises a microvalve capable of controlling the flow of a fluid. The microfluidic chip has three position states, so as to control different fluids in the chip to sequentially flow in the chip. The microfluidic chip and the microvalve have simple structures, are convenient to assemble, are reusable, and can avoid the possibility of mutual contamination between fluids.