Scientifically and effectively evaluating the influences of historical temperature and relative humidity on organic cultural relics is the basis for optimizing the strategy of setting temperature and relative humidity in the storeroom, and balancing the effectiveness and sustainability of preventive conservation of cultural relics. Lifetime multiplier (LM) and preservation index (IPI) are advanced indexes which have been used to quantitatively evaluate the chemical degradation risk of organic cultural relics. Equilibrium moisture content (EMC) and response relative humidity (response RH) are advanced indexes which have been used to quantitatively evaluate the mechanical damage risk of organic cultural relics. We analyzed the reflection of the above indexes on the actual historical temperature and relative humidity in 29 storerooms, which have different temperature and relative humidity characteristics. The applicability of these indexes to evaluating historical temperature and humidity of organic cultural relic storerooms was studied accordingly. It was found: 1) LM could be used to evaluate the chemical degradation risk of organic cultural relics in a single media storeroom, and IPI was more suitable for evaluating the general chemical degradation risk of fragile organic cultural relics in a mixed-media storeroom; 2) EMC was a general index to evaluate the mechanical damage risk of organic cultural relics, and response RH could be used to evaluate the mechanical damage risk of organic cultural relics which had been adapted to its historical environment.