The invention discloses a preparation method of a terpyridyl zinc complex and application. The preparation method comprises the following steps: in a DMSO (Dimethylsulfoxide) solvent system, performing a substitution reaction on carbazole, bromohexane and a 50% sodium hydroxide solution at 50 DEG C; in a dichloromethane solvent system, performing a local selective bromination reaction on a compound 1 and NBS (N-Bromobutanimide) at 25 DEG C; in a nitrogen environment and in a dried diisopropylamine solution system, performing a Sonogashira coupling reaction on p-bromo benzaldehyde, trimethylsilylacetylene, copper iodide and (beta-4)-platinum at 80 DEG C; in a nitrogen environment and in a dried diisopropylamine and tetrahydrofuran solution system, performing a Sonogashira coupling reactionon a compound 2, a compound 3, copper iodide and (beta-4)-platinum at 80 DEG C; in an ethanol solvent system, performing a Krohnke middle ring formation method reaction on an alkyne-containing compound 4, diacyl pyridine and potassium hydroxide at 25 DEG C; stirring a terpyridyl compound and trifluoro zinc sulfonate in methanol. The preparation method is simple in step and gentle, and water printing of a product is achieved.