The invention discloses a synthetic method of MOFs (metal-organic frameworks) with good fluorescence property and an application of the MOFs to detection of parathion in pesticide residues. The synthetic method comprises the following steps: porphyrin with a large conjugated structure, 1,2,4,5-tetrakis(4-carboxyphenyl)benzene and Zn(NO3)2.6H2O are fed to a beaker, then N,N-dimethylformamide is added, and the substances are mixed ultrasonically; the uniformly mixed solution is poured into a reactor for a reaction; a reaction product is centrifuged, an upper liquid is removed, and ethyl alcohol is added, and the reaction product is subjected to repeated centrifugal washing three times or more; solid powder of the MOFs is obtained after high-temperature drying. Parathion has a specific quenching effect on fluorescence signals of the MOFs, and fluorescence quenching is more obvious when more parathion is added; when the concentration of parathion is in the range of 5-1,000 ppb, the fluorescence intensity in inverse proportion to the logarithm of the parathion concentration, and high-sensitivity and high-specificity detection of parathion is realized.