The Monk-White illusion is a visual illusion phenomenon that relies on colour assimilation and perceptual properties, and has gained widespread use on display-like two-dimensional planes. However, the application of the Monk-White illusion in real-world environments is relatively limited, and there is a lack of research on its application in a systematic way. The aim of this study is to explore the performance properties of the Monk-White illusion in real-world environments and the factors that influence them. This study focuses on: what factors influence the performance of the Monk-White illusion in real-world environments? How do the effects of the illusion and the perception of the number of shades of object colours differ between the display and the real environment? In this study, a qualitative research method was used to collect subjects’ visual discrimination judgements on the intensity of the effect and the perception of the number of hues of the Monk-White illusion samples through field tests. It was found that factors such as frame colour (hue, lightness, purity, spacing) and object colour distribution influenced the Monk-White illusion and that the effect was stronger and the number of tones perceived was greater in the display than in the real environment. This study complements the lack of research on the application of the Monk-White illusion to real-world environments. The results of the study provide designers with design guidelines on how to effectively utilise the Monk-White illusion in real-life product applications to enhance the visual experience and interest of the product.