One of the most common diseases in seal impressions books is ink oil permeation caused by the aging of ink oil. Some research shows that ink oil permeation can not only form yellow or brown oil stains around seals, but also reduce the pH values of paper, which affects the long-term preservation of seal impressions books. Through a simulated aging experiment using six kinds of oils commonly used in the red ink paste, it was found that there were many problems, such as discoloration, pH value decrease and oil permeation after aging. GC-MS was used to analyze the oil samples before and after aging, and the result show that the content of unsaturated fatty acids was reduced and aliphatic carboxylic acids such as azelaic acid were formed during the aging process. The compositional changes in the aging process of oil lead to a series of problems such as discoloration, acidification and permeation. For the conservation of seal impressions books, targeted treatments against the aging of oil should be carried out.