Temperature and relative humidity are basic indicators for the monitoring of museum environments. In order to better understand a great many temperature and humidity monitoring data, the K-line diagram was introduced to the temperature and humidity evaluation system. According to the four elements of K-line diagram, the initial value, the end value, the maximum value and the minimum value during the sampling period are defined and correspond respectively to the initial price, the closing price, the highest price and the lowest price of K-line diagram (in the business world, where K-line originated). Using the continuous monitoring data from a temporary exhibition, we evaluated the temperature and humidity in the exhibition hall and some showcases using K-line diagrams. The comparison between the regulation effects of active humidity control and passive humidity control provides a reference for the selection of humidity control methods for short-term exhibitions. This paper establishes an environmental monitoring data analysis model for the data processing of temperature and humidity in museum environments and provides an intuitive discussion plan for the environmental quality assessment of cultural relic conservation.