Lignin is another most abundantly available organic compound/biopolymer after cellulose and greatest source of natural aromatic compounds on earth. Lignin comes under the category of organic polymer and play an important role in the formation of “cell walls” in wood and lend “rigidity to the cell walls”. In the “pulp and paper sector”, lignin is present in the “black liquor” which is received after the pulping or delignification process. There is increasing need of extraction, purification and characterization of the lignin to explore its application in various industries. The analytical techniques of lignin is important and therefore, the quantitative and qualitative analytical methods of lignin is required to be explored for better utilization of lignin in various industrial applications. In the scope of this chapter, the details of analytical techniques of lignin has been mentioned including the characterization of chemical structure, particle size and molecular size determination.