First of all, we should know the specific regulations of Dujiangyan to determine whether dogs are allowed to enter. You can get an accurate answer by investigating official website, contacting the scenic spot management department or consulting relevant tourism information.
Secondly, if Dujiangyan allows dogs to be brought in, you need to pay attention to the behavior and normal manners of dogs in tourist places. Make sure your dog doesn't bite, run around and disturb other tourists. Before that, please make sure that you and your dog have good behavior and basic training.
Finally, even if Dujiangyan allows dogs to come in, I suggest you make plans and preparations in advance. Please make sure that you have enough food, water and facilities to walk the dog, and give the dog a comfortable and safe environment.