Abstract: The present invention relates to a method for detecting time-resolved fluorescence based on a principle of phase balanced frequency multiplication modulation. A stimulating light source modulated by using a baseband signal acts on a to-be-measured target to trigger fluorescence, so that the fluorescence intensifies and decays periodically; then, a frequency-doubled square signal is used to control a sampling period and divide an ascending period of the fluorescence into two and a decay period of the fluorescence into two; after independent sampling is performed separately, sampling differences of the two parts are separately calculated and then added to obtain an intensity representative value of a fluorescence signal and to obtain a concentration value of the to-be-measured target.