The invention discloses a method for measuring the concentration of molecular targeted drugs in 
plasma by using ultra-
high performance liquid chromatography tandem mass spectrometry. The method comprises the following steps of respectively dissolving anlotinib, 
ceritinib and 
ibrutinib by adopting 
acetonitrile in order to prepare a 
standard curve working solution, and dissolving 
diazepam by adopting 
methanol in order to prepare an 
internal standard substance working solution; respectively adding 0-5 microliters of 
standard curve working solution into blank 
plasma to make up to 50 microliters, carrying out vortex to prepare a 
standard curve plasma sample, adding the 
internal standard substance working solution, carrying out vortex and 
centrifugation, taking supernate, carrying out UPLC-MS / MSquantitative analysis, and drawing a standard curve; and precisely sucking to-be-detected plasma with the concentration of 50 microliters, adopting the same sample 
pretreatment method, and measuringthe concentration of the anlotinib, the 
ceritinib and the 
ibrutinib according to a standard curve of the batch. According to the method, the 
blood concentration of various anti-tumor molecular targeted drugs can be measured simultaneously, the method is high in sensitivity, strong in specificity, rapid and good in reproducibility and is suitable for clinical high-
throughput simultaneous detectionand monitoring of various anti-tumor molecular targeted drugs.