Abstract: Disclosed is an implementation method for ultrasensitive Brink control for a delayed enzymatic reaction based on DNA strand displacement (DSD), relating to the field of feedback control technology based on DSD in biological systems. The method includes obtaining an enzymatic reaction process model with time delay; constructing a CRN-based Brink controller; obtaining a static mapping expression between an output of the Brink controller and an output of the system under a steady state condition; constructing a Brink controller by DSD reaction; obtaining a time delay representation, and applying it to DNA implementations of the enzymatic reaction process model; and combined with the Brink controller, controlling a delayed enzymatic reaction process model. The present invention is structurally free of subtraction, reduces the number of abstract chemical reactions required to implement, and greatly simplifies DNA implementation.