From early AD to mid-19 century, people mainly use the natural organic substance (such as animal and plant extracts) for qualitative analysis or quantitative analysis. From the second half of the 19th century to the 1920s, it had begun to appear of artificially synthetic organic reagent such as using potassium acetate xanthan for test of nickel, copper, and molybdenum; using morin for test of aluminum; using diazo coupling reaction for the detection of Nitrite; using α-β-nitroso naphthol for detection of cobalt; using dimethyglyoxime for nickel test. After the proposal of the special-effects group in the 1930s and the proposal of theoretical analysis of functional groups theory in 1950s, people had carried out large-scale screen of organic reagents in search of special-effects analysis groups for different ions and had successfully synthesized a lot of agents of practical value (such as copper reagents, new copper agent, cadmium reagents, beryllium reagent, thorium reagents, etc.). Before the 1950s, the complex compound, in analytic chemistry, is mainly used in the aspects of the precipitation reaction of a binary chelate for the qualitative detection, precipitate isolation and gravimetric separation and other aspects. In the early 1950s and 1960, it is mainly in the form of complexometric titration. From the beginning of the late 1960s, the main focus has been moved to the photometric analysis. Meanwhile, it has been also developed of chelate organic solvent extraction.