Paraloid is the trade name of a series of acrylic resins. Paraloid products are one of the most useful materials in cultural relics conservation, which is usually applicable to a wide range of artifacts for consolidation, sealing and bonding. Among these products, Paraloid B-72 is the most representative one, widely used in art conservation at home and abroad. There are many reports on application cases, performance evaluation and aging mechanism research of Paraloid B-72. However, the other Paraloid products are obtained less attention due to limited domestic applications, and the aging performance research has not yet been conducted. This paper systematically evaluated the UV aging performance of Paraloid B-72, Paraloid B-44, Paraloid B-48N and Paraloid B-67. By using infrared spectroscopy to track the molecular structure changes during the 3864 h UV test, the aging mechanisms of these Paraloid products were further discussed and semi-quantitatively characterized. The results show that among the four Paraloid acrylic resins, the color and gloss of B-72 do not change significantly before and after aging test, while B-48N and B-67 color change greatly, and the gloss of B-44 decreased the most. During the aging process, the chain scission reaction and a certain degree of cross-linking reaction occur inside the acrylic resins, which is manifested in the weakening of the absorption of main functional groups and the increase of the carbonyl index (CI). According to the semi-quantitative results of the relative intensity of the main functional group absorption peak C=O, it can be reflected that B-72 has the best photostability. B-48N and B-44 perform slightly better than B-67. B-67 may be due to the low tertiary hydrogen bond energy on the isobutyl group, which is easy to absorb UV spectral energy and produce free radical oxidation reactions. Therefore, B-67 has the worst light aging resistance. In the comprehensive evaluation of the light aging performance of four Paraloid acrylic resins, B-72 has the best light stability, followed by B-44 and B-48N, and B-67 is the least suitable conservation material for outdoor cultural relics. The conclusions of this study are expected to provide some scientific suggestions for the first-line cultural relics conservators when choosing Paraloid acrylic resins as the conservation material.