A detecting device for detecting physiological parameters of a biological tissue includes a light source, at least one light detector, a package, an outer cover, and an optical microstructure. The light source is configured to emit a first beam and a second beam. The package is disposed on the light source and the light detector and is located on the transmission paths of the first and second beams. The outer cover covers the light source, the light detector and the package, and includes a top surface. The optical microstructure is located in the transmission paths of the first and second beams, and is arranged in parallel with the top surface of the outer cover. The optical microstructure includes at least one set of circles of different radii, and is made of a diffractive optical element, a holographic optical element, a computer-generated holographic element, a fresnel lens or a lens grating.
