<p>Honey bees make propolis from resins depending on resinous plants available in a particular environment. The aim of this work was to identify the plant origin of Chinese propolis. Through a combination of phytochemical analysis and behavior observation of worker bees, we find that worker bees collected resin on the bud surface of <i>Populus canadensis</i> Moench, and bud resin of <i>P. canadensis</i> presented high similarities between resin in worker bees’ corbiculae and propolis. The results reveal that <i>P. canadensis</i>, a hybrid variety of <i>Populus nigra</i> L. × <i>Populus deltoides</i>, is a plant origin of Chinese propolis. Characteristic components of Chinese propolis included benzyl caffeate, phenethyl caffeate, cinnamyl caffeate, cinnamyl <i>p</i>-cinnamate, pinobanksin-3-acetate, chrysin, pinocembrin, galangin, 5-methoxy pinobanksin, and pinobanksin. These compounds represented more than 80% of the total phenolic contents. This finding will help evaluate the quality and authenticity of poplar type propolis.</p
