Previous studies have highlighted the advantages of established brands in the Chinese market, but few have explored their cross-boundary innovation strategies in response to fierce competition. With the establishment of “China Brand Day” and the rise of Chinese trends, many established brands aim to attract a new generation of customers and invigorate their brand vitality through cross-boundary innovation. This paper seeks to address gaps in previous research on cross-boundary innovation among established brands and offers insights into strategies for brand activation. This paper introduces the theory of customer inspiration and investigates how the cross-boundary innovation of established brands influence customer purchase intentions and loyalty through three psychological experiments. Experimental results demonstrate that cross-boundary innovation by established brands can inspire customers. The Inspired-By and Inspired-To mediate the impact of cross-boundary innovation on customer purchase intentions and loyalty, while mental simulation moderates the effect of cross-boundary innovation on customer inspiration. This paper advances our understanding of cross-boundary innovation among established brands, providing practical guidance on brand activation amidst the Chinese trend phenomenon