In recent years, the number of live streaming platforms and the number of viewers have exploded. For example, in China, there are already more than 100 live streaming platforms as well as more than 300 million consumers. In live commerce, streamers use 'information overload' to affect purchase decisions, by making it difficult for consumers to think systematically; however, the mechanism of impact in this way has not been confirmed. In order to clarify how information overload affects users' purchasing decisions in live commerce, this study introduces information overload from the perspective of "Heuristic-systematic model" to develop a research model. And 400 respondents were randomly recruited through various SNS platforms in Guangdong Province, China from July 1 to July 20, 2022 using a random survey method, and finally 297 valid sample data were obtained. To verify the validity of the model and to illustrate the impact of information overload marketing on consumer purchase decisions in live commerce this study conducted an empirical analysis using Smart PLS 3.0. The findings show that perceived product quality and fit, and streamer influence and expertise, positively affect consumers' purchase intentions. The information overload strategy can significantly reduce consumers' perceptions of merchandise fit and enhance their perceptions of streamer influence and expertise. The results of this study provide a theoretical basis for marketing strategies in live commerce, and enrich literature in the field of marketing.