Organic cultural relics can be easily infected by fungi in the muggy environment of Southern China. As a result, cultural relics can suffer irreversible destruction. To prevent the growth of mildew, two methods are usually used. One is to control the temperature and humidity of the environment and the other is to use mildew preventives. However, these two methods can be limited by economic concerns and scoope of application. To address the above problems, the Nanjing Museum promotes the research on fungicidal papers used for collections of cultural relics. Some common, safe mildew preventives used in museums were chosen for testing. Their inhibition zones and fungicidal effectiveness times were compared. The results indicate that LAg003, NMF1, and MD have better inhibition effects against fungi commonly seen in cultural relics, therefore they could be used in the fungicidal papers.