Synthesis method of DNA coding molecule library and DNA template

The invention discloses a synthesis method of a DNA coding molecule library and a DNA template. The method comprises the following steps: (1) carrying out DNA coding; (2) constructing the DNA template which comprises a hairpin-shaped PCR binding region PBS-1, N reaction regions t and a PCR primer binding region PBS-2, wherein the hairpin-shaped PCR binding region PBS-1, the N reaction regions t and the PCR primer binding region PBS-2 are connected successively, the N reaction regions t are correspondingly combined to N structural units, and a non-classical inosine base group does not exist in the reaction regions; (3) carrying out DNA coupling; (4) carrying out enzyme linking; (5) carrying out chemical reaction; (6) coding the chemical reaction of structural groups R1 by illumination; and (7) successively repeating the step (3), the step (4), the step (5) and the step (6) on the remaining structural units for N-1 times to realize coding of chemical reaction of the N structural groups R so as to finish synthesis of the DNA coding molecule library, wherein N is greater than or equal to 2. By the method, a template T guides synthesis of the whole molecule library, and the synthesis is unrelated to specific n, m and o values and is also unrelated to the number of compounds in the molecule library.