The invention discloses a preparation process of a leak protection plugging agent along with drilling based on the control of monomer concentration. The preparation process comprises the following steps: (a) purifying AM (acrylamide) and AMPS (2-acrylamido-2-methyl propane sulfonic acid) for later use; (b) weighing AA (acrylic acid), hydrolyzing and transferring into a reactor in a super constant-temperature water bath; (c) adding a certain amount of cross-linking agent; (d) adding AM and AMPS solutions, and regulating the pH value of a reaction system to 7, wherein the monomer concentration is 14.3%-18.2% by weight; (e) introducing inert gas for deoxygenation, stirring and adding an initiator; and (f) regulating the temperature to reaction temperature, and performing polymerization reaction for a certain period of time to get a target product. According to the preparation process disclosed by the invention, the leak protection plugging agent along with drilling can be successfully prepared by controlling the monomer concentration in reaction process, the preparation process further has the advantages of high production efficiency, simple production process, simplicity in operation and capability of greatly reducing the production cost, various performances of the produced leak protection plugging agent along with drilling are far better than those of an existing product, and the leak protection plugging agent along with drilling is further conductive to field well leakage treatment.