In Taiwan, temples were decorated with painted and sculptured auspicious images that promote the communication between worshippers and deities. In this study, we adopted grounded theory and ethnography with applied semiotic theory to analysis the semiotic meanings of the auspicious images of Taiwanese folk religion temple, identify the semiotic characteristics of the images, and summarize the signs associated with the images. A total of 126 image samples were collected from field study, and the KJ method was subsequently performed to categorize and analyze the samples. Finally, some significant findings were obtained, the functional aspects of the aforementioned images mostly belong to the categories of symbol and homonymy, whereas their mental aspects belong to the categories of psychological and physiological requirements. In sum, humans perceive the world through signs and that human life is the semiotization of the world, although Eastern and Western cultures are characteristically different, they share much similarity in communication methods. The findings of this study can foster the understanding of the truth, goodness, and beauty of the architectural decoration of temples in Taiwan and the modesty, hospitality, generosity, and religiosity of Taiwanese society.