A method for detecting an overlay precision and a method for compensating an overlay deviation are provided. The method for detecting the overlay precision includes providing a wafer to-be-detected, where the wafer to-be-detected includes a photoresist layer which has been exposed and developed; performing a first detection on the wafer to-be-detected using an optical overlay precision measurement and acquiring first overlay precision information of the photoresist layer; performing a second detection on the wafer to-be-detected using the optical overlay precision measurement, and acquiring second overlay precision information of the photoresist layer, where a wavelength or a polarization direction of a light source of the second detection is different from a wavelength or a polarization direction of a light source of the first detection; and acquiring overlay precision deviation information of the wafer to-be-detected according to the first overlay precision information and the second overlay precision information.