The invention provides a method for fast detecting pesticide residue, which relates to a fluoroscopic detection method of organic phosphor pesticide. The invention utilizes a fluorescence spectrophotometer with program, uses porphyrin compounds as fluorescence indicating agents and developers, and detects the organic phosphor pesticide in the liquid state porphyrin detection solution through preparing a porphyrin solution, an organic phosphor pesticide solution and a liquid state detection solution. The invention has the characteristics of high detection sensitivity, low detection limitation, high accuracy, simple and convenient operation, convenient and fast in-site detection, high economical efficiency, convenient popularization and application and the like. The invention can be widely used for the trace amount detection of foodgrain, food and the like which easily contain the organic phosphor pesticide residue, and can also be used in the security assessment of food such as vegetables, fruit and the like and the environment detection.