In this work, binding interactions of artemisinin (ART) and dihydroartemisinin (DHA) with human serum albumin (HSA) and bovine serum albumin (BSA) were investigated thoroughly to illustrate the conformational variation of serum albumin. Experimental results indicated that ART and DHA bound strongly with the site I of serum albumins via hydrogen bond (H‐bond) and van der Waals force and subsequently statically quenched the intrinsic fluorescence of serum albumins through concentration‐dependent manner. The quenching abilities of two drugs on the intrinsic fluorescence of HSA were much higher than the quenching abilities of two drugs on the intrinsic fluorescence of BSA. Both ART and DHA, especially DHA, caused the conformational variation of serum albumins and reduced the α‐helix structure content of serum albumins. DHA with hydrophilic hydroxyl group bound with HSA more strongly, suggesting the important roles of the chemical polarity and the hydrophilicity during the binding interactions of two drugs with serum albumins. These results reveal the molecular understanding of binding interactions between ART derivatives and serum albumins, providing vital information for the future application of ART derivatives in biological and clinical areas. Interaction mechanisms of artemisinin and dihydroartemisinin with HSA and BSA were systematically investigated via multispectral and molecular docking techniques. Artemisinin and dihydroartemisinin statically quenched the intrinsic fluorescence of HSA and BSA under van der Waals forces and hydrogen bond forces. Artemisinin and dihydroartemisinin changed the secondary conformation of HSA and BSA to varying degrees and decreased their activities to some extent.