<p>Increasing global emphasis on health has driven significant demand for bioactive compounds with nutritional and nutraceutical properties, exemplified by the growing market prominence of protein-rich Chlorella pyrenoidosa, whose commercial value rises with economic growth and consumer awareness of functional nutrition. In this study, a Chlorella pyrenoidosa beer was developed using Chlorella pyrenoidosa and Clausena lansium as experimental materials, aiming to promote the development of microalgae industry by using the speciality fruits, and assessing the effects of adding Chlorella pyrenoidosa on the physicochemical indexes of the fruit beer and the antioxidant capacity. In addition, this study used gas chromatography-mass spectrometry (LC-MS) to determine and evaluate the changes in aroma substances before and after fermentation of Chlorella pyrenoidosa, and explored the changes in amino acids and fatty acids before and after Chlorella pyrenoidosa treatment. The results showed that Chlorella pyrenoidosa-Clausena lansium fruit beer (CPCL) was processed as follows: the addition of Clausena lansium pulp was 9.8%, the addition of Chlorella pyrenoidosa was 0.85&#xa0;g/100 L, and the addition of yeast was 1.45%. Compared to the Chlorella pyrenoidosa-free fruit beer (CL), the CPCL showed significantly higher scavenging capacity for 1,1-diphenyl−2-trinitrophenylhydrazine radical (DPPH), hydroxyl radical (OH) and ABTS. The content of the flavouring substance choline phosphate was reduced by 99.161% and guanosine by 27.673%. These findings highlight a new developmental pattern of Chlorella pyrenoidosa that enhances the antioxidant capacity of the food products and improves the quality and economic value of Chlorella pyrenoidosa.</p> Graphical abstract <p></p>