The invention discloses a Method for rapidly detecting pesticide residues in leafy vegetables. According to the method, a self-developed ion source equipped with a thermal desorption device is connected with a serial quadrupole mass spectrometer to form a detection instrument, an MRM mode is adopted for monitoring, complex pretreatment steps are not needed, only the surfaces of the leafy vegetables need to be scraped and then directly detected on a machine, the whole process is simple, convenient and fast, the detection time of a single sample is shorter than 1 min, and the method is particularly suitable for monitoring pesticide residues in leafy vegetable agricultural products which are not easy to store and short in shelf life. Compared with a national standard rapid detection method, the method has precise results, is suitable for detecting various pesticides such as triazole, benzimidazole and aniline besides organophosphorus and carbamate.