The invention provides a method for simultaneously detecting particulate organics and dissolved organics in water body, comprising the following steps: firstly, collecting water body samples and setting an excitation wavelength, an emission wavelength and a scanning speed of a fluorescence spectrophotometer; secondly, determining excitation-emission three-dimensional fluorescence spectrums of all samples and ultrapure water; thirdly, subjecting the three-dimensional fluorescence spectrums of the samples to raman scattering correction by using the three-dimensional fluorescence spectrum of the ultrapure water; fourthly, exporting a data matrix of the three-dimensional fluorescence spectrums obtained by the raman scattering correction for data conversion; fifthly, subjecting data obtained after the data conversion of all samples to principal component analysis; sixthly, identifying components of organics in water by utilizing a factor score matrix graph which is drawn from a factor score coefficient matrix through conversion; seventhly, calculating relative content of the particulate organics and the dissolved organics in the water body based on principal component analyzing results. The method provided by the invention has the advantages of little demand for samples, high detection sensitivity, no damage to sample structure and environmental protection.