The invention provides a confocal microscopy measuring device based on measured surface fluorescence excitation, and belongs to the technical field of surface topography measurement. The confocal microscopy measuring device comprises a laser device, a collimation beam expander, a polarizing beam splitter, a quarter-wave plate, a detection objective lens, a tested part, a collection objective lens, a pinhole and a detector, wherein the collimation beam expander and the polarizing beam splitter are configured on a collineation light path of the laser device along the light propagation direction; the quarter-wave plate, the detection objective lens and the tested part are configured on the reflection light path of the polarizing beam splitter; the collection objective lens, the pinhole and the detector are configured on the transmission light path of the polarizing beam splitter; a narrow band filter is contained inside the detector; and the tested part is borne by a micrometric displacement objective table, and the surface of the tested part is coated with a film in a vacuum evaporating coating method. By means of the design that surface characteristics of the tested surface are changed through film coating, the fact that measurement light can return back to a detection system after being reflected by the tested surface is guaranteed, the difficult problems of detection of a large numerical aperture (NA) and high gradient surface are resolved, and the confocal microscopy measuring device is suitable for ultra precise measurement of three-dimensional shapes with large NA and high gradient spherical surfaces, aspheric surfaces and free-form surfaces.