Hydrogel temporary plugging agent has good rheological properties before gelling, easy injection, deformability after gelling, and adjustable plugging strength. It has unique advantages in plugging operations. However, the existing gel-type plugging agents generally have the problems of difficult gel breaking, nonspontaneous degradation, and uncontrollable degradation. In this paper, a functional cross-linking agent was synthesized from dimethylamino ethyl acrylate and dibromo-p-xylene. The cross-linking agent includes a quaternary amine salt structure, ester group, and conjugated nonplanar central core. The hydrogel system developed with the cross-linking agent as the core can self-degrade at a certain temperature. In addition, by introducing a built-in degradation catalyst and the cross-linking agent to produce a synergistic effect, the degradation process of the hydrogel can be controlled and adjusted. The results showed that at 50–90 ℃, the gel forming time of the hydrogel was 1–4 h, the strength could reach Grade I rigid gel, and it had good gel forming performance; By adjusting the amount of cross-linking agent and built-in degradation catalyst, the hydrogel degradation time can be adjusted (7–14 days), and the viscosity after degradation can be controlled (<10 mPa s); In the core plugging experiment, the plugging strength of the gel plugging agent can reach up to 75 MPa/m, and the core damage rate after degradation is less than 5%, with good pressure bearing performance and degradation performance. The gel plugging agent has a good effect in the field application of AXX-XX well. After plugging, the wellhead oil pressure decreases from 15.7 MPa to 0 MPa. After reaching the self-degradation time, the water injection recovery rate of the water injection well reaches 100%, meeting the requirements. This type of hydrogel has a good plugging effect and excellent self-degradation performance. It can be used for various temporary plugging operations and has broad application prospects.