The invention provides a preparation method of a transmission electron microscope for a section of a weak-bond strength brittle bonding sample and relates to transmission electron microscopes. The preparation method comprises the steps of bonding two Si liner sheets to the back of a bonding sample with AB glue so as to form a liner sheet for sharing a grinding action force, bonding the Si liner sheet to two ends of a bonding section with AB glue, and fixing two ends of the bonding section to prevent a bonding interface from being torn by a shear force and a pressure in the grinding process, soas to obtain a section sample for thinning ions. The weak-bond strength section is fixed through the Si liner sheet by virtue of a section edge binding method, so that the breakage of the bonding interface in the grinding process can be avoided; and the sample is thinned and polished by the cooperation of diamond powder and abrasive paper, so that the section of the sample can be effectively andrapidly thinned to the thickness of smaller than 30 microns. The preparation method is a simple and rapid novel TEM section sample preparation method with low cost and high success rate.