Native advertising and display advertising are often combined as each serves a distinct business purpose. However, their influential relationship has not been thoroughly examined, which may blind platforms to making sound advertising portfolio decisions. This study explores the causal effect of display advertising on native advertising performance in mobile contexts, and the moderating roles of sellers’ (i.e., restaurants’) average rating and chain status. A field quasi-experiment on a large mobile e-commerce platform shows that following the introduction of display ads, the clicks, bids, and costs of native ads decreased significantly by 6.6%, 6%, and 11.9%, respectively, while the total advertising cost increased by 18.4%. These findings suggest a partial substitution effect between the two ad types. Furthermore, the negative impact of display ads on the effectiveness of native ads intensifies as the average ratings decline, and is most pronounced in regional chains. This study enriches previous literature by elucidating the influential relationship between mobile display and native advertising, and provides valuable insights for platform managers to develop effective marketing strategies.