Principle agarose gel electrophoresis is an electrophoretic method using agarose as a support medium. The main difference between its analytical principle and other support electrophoresis is that it has the dual role of "molecular sieve" and "electrophoresis". Agarose gel has a network structure, material molecules will be resisted when passing through, large molecules in the surge of material resistance, so in gel electrophoresis, the separation of charged particles depends not only on the nature and number of net charge, but also depends on the size of the molecule, which greatly improves the ability to discriminate. However, because its pore size is too large compared to proteins, its molecular sieving effect is negligible for most proteins, and it is now widely used in the study of nucleic acids