Pathogenic nematodes in diseased tissues can be obtained from live nematodes by direct picking with a needle, funnel separation or mashing the diseased tissues for separation, etc. In order to identify common nematodes and to make general observations on their morphology and structure, temporary slides can be made from live nematodes, and in order to further scrutinize and recognize their taxonomic characteristics, live nematodes need to be killed and fixed, and sometimes stained, to be made into permanent slide specimens, and in order to To observe the interrelationship between nematodes and host tissues, paraffin sections of host and nematode tissues are also made.

Nematode staining solution (multicolor blue method) is mainly composed of methyl blue, ethanol, glycerol, etc. After killing and fixing the nematodes by heating, the nematodes are stained with multicolor blue and observed, the staining principle is based on the different hydrogen ion concentration and physiological state of various organs of the nematodes during fixation, and this method can be used to study the structure of the nematodes' different organs better.