A method for directly analyzing a 
lung cancer tissue sample based on the tissue electro-spray 
ionization mass spectrometry concretely comprises the steps that an electro-spray extraction 
ionization source in the 
tissue sample is set up; an extraction agent, namely, methyl 
alcohol is sucked through a micro-
syringe connected with a 
quartz capillary, the extraction agent is dripped on the surface of the sample through the 
quartz capillary, and an 
injection pump controls the micro-
syringe; the 
lung cancer tissue sample is 
cut into a piece of which the volume is 1 mm3 and placed at the tip of an 
acupuncture needle, and the needle tip is inserted into the sample and keep unexposed; the distance between the front end of the sample and an inlet of a 
mass spectrometer is adjusted, and the 
tail end of the 
acupuncture needle, the front end of the sample and the inlet of the 
mass spectrometer are adjusted to be in a horizontal coaxial state; 
DC voltage is applied on the 
acupuncture needle, so that extraction, 
desorption and 
ionization happen on the sample, and the sample generates spray which enters the mass 
spectrometer. According to the method, the information of molecules in the sample can be directly and quickly obtained, and the result shows that the method is a 
mass spectrometry method which has the advantages that the device is simple, manufacturing cost is low, ionization efficiency is high, and damage to the sample is small.