<p>E-commerce live streaming has emerged as a novel electronic shopping method, progressively becoming a pivotal force in the transformation of the retail industry and driving consumer growth and economic prosperity. Compared to traditional TV shopping channels, live e-commerce platforms provide celebrities with significant autonomy in their marketing strategies. This study develops a marketing model to analyze new product promotions through live-streaming collaborations between brand owners and celebrities, focusing on balancing economic gains with the sustainability of the following base. The findings reveal that the evaluation of the product-market fit of a celebrity and their professional competence significantly influence the promotional strategies. Highly professional celebrities favor honest recommendations for high-fit products, while deceptive promotions mitigate risks for low-fit products. Moderately professional celebrities adopt nuanced strategies, shifting between honest and deceptive promotions based on product-market fit levels, while low-professionalism celebrities consistently favor deceptive promotions due to inaccurate product judgment. Furthermore, the coefficient of follower traffic value and follower concentration shape the effectiveness of the strategy, forming customized approaches for celebrities with short-sighted, mature, and new arrivals. These insights optimize marketing strategies by aligning them with product traits, audience composition, and engagement dynamics.</p>