A brand logo is the visual representation of a brand. It plays a massive part in determining customers’ attitudes. In both the Chinese and overseas markets, letter cases in brand logos have puzzled scholars and managers alike. Yet to this day, few researchers have studied the influence of letter cases on brand logo design and its moderators. Based on Symbolic Association Theory, the current research uses 2 experiments to test the correlation between letter cases; customer perceived brand power and attitude. Among existing theories, researchers have focused on the impact of brand logos' color, shape size, clarity, border, orthographic slant and other overall elements on consumer perceptions, but few studies have focused on the impact of letter case type in text brand identity on consumer perceptions and attitudes. Existing theory suffers from 3 deficiencies: first, existing studies focusing on the effect of letter cases attribute the impact mechanism to reading fluency, arguing that the use of capital letters in sentences reduces reading efficiency and thus affects reader behavior and that this effect becomes less significant with shorter sentences and words, while brand logos are usually shorter in length; there are also studies It has also been found that uppercase symbols are more recognizable and memorable than lowercase logos. This shows that the existing theoretical mechanisms are contradictory and not applicable to brand identity. Second, previous studies can only explain consumers' preference for lowercase letters but cannot explain why consumers sometimes prefer uppercase logos. Third, due to the lack of relevant studies, the boundaries of consumer regulation of letter-case brand preferences are still unclear. To fill these 3 gaps, we focus on answering 3 questions in this study. First, how the case of letters in brand logos affects consumers' attitudes. Second, what are the psychological mechanisms involved? Third, what types of brands do upper/lower case logos apply to, respectively? A total of 3 hypotheses are proposed in this paper to address these questions. And this study uses three separate sets of experiments to test the proposed hypotheses. Experiment 1 examines the main effect of case identification on consumer attitudes and the mediating impact of perceived power tendencies, and Experiment 2 examines the moderating effect of perceived luxury. This study confirms through 2 sets of experiments that letter case in brand identity further influences consumers' attitudes toward brands by affecting their propensity to perceive brand power, which is moderated by the brand's perceived level of luxury. Expressly, this study confirms that uppercase letters enhance consumers' perceived propensity to display brand power, while a high propensity to show power is beneficial only for brands with more elevated perceived luxury; for brands with lower perceived luxury, lowercase letters with a weaker tendency to display power are more appropriate. The results show that capital letters are more suitable for brands of a high level of luxury, while for brands of a lower level of luxury, the less persuasive lowercase letters are more appropriate. This research not only expands and enriches the scope of SAT (Symbolic Association Theory) but also provides managers and designers with constructive guidelines for logo design.