A reaction method with a homogeneous-phase supercritical fluid includes introducing a first fluid into a mixing chamber. A mass is less than or equal to that can be absorbed by the molecular sieve component, totally absorbing the first fluid by the molecular sieve component. A second fluid is introduced into the mixing chamber with a mass being greater than that can be absorbed by the molecular sieve component. A temperature and a pressure in the mixing chamber are adjusted to a critical temperature and a critical pressure of the second fluid, respectively, releasing the first fluid in supercritical phase from the molecular sieve component into the mixing chamber, followed by homogeneously mixing with the second fluid in supercritical phase in the mixing chamber to obtain a homogeneous-phase mixing fluid. The homogeneous-phase mixing fluid is then introduced into a reaction chamber connected to the mixing chamber.