The rapid and efficient adsorption of heavy metal Cr by Chlorella pyrenoidosa is combined with X-ray fluorescence (XRF) spectroscopy technology for rapid detection of heavy metals in the field. Rapid detection of heavy metal Cr in water is realized by XRF spectroscopy technology. The research shows that Chlorella pyrenoidosa can achieve high-efficient and stable adsorption for heavy metal Cr within 5 min, and the optimal pH value range of adsorption reaction is 6-8. The optimal mass concentration of Chlorella pyrenoidosa is 100 mg·L^-1. Under the optimal adsorption reaction condition, the rapid enrichment of heavy metal Cr in water by Chlorella pyrenoidosa is achieved by suction filtration-membrane enrichment, and then XRF spectrometry measurement is performed. When the enrichment volume of the reaction solution is 10 mL, and the XRF signal accumulation time is 2 min, there is a positive linear relationship between the net integral fluorescence intensity of the Kα characteristic spectral peak of heavy metal Cr and the concentration of Cr in water to be tested, and the correlation coefficient R² is 0.9967. The detection limit of the method for heavy metal Cr in water is 0.0299 mg·L^-1, which is significantly lower than the standard limit of 0.05 mg·L^-1 of Cr in Class Ⅱ water stipulated in Environmental Quality Standards for Surface Water (GB 3838—2002). This method is used to test the recovery of water samples from the Kuanghe River in Hefei City, Anhui Province. The recovery rate of heavy metal Cr ranges from 90.00% to 101.24%, and the precision of 10 repeated measurements ranges from 1.59% to 2.66%. Therefore, the accurate detection of heavy metal Cr in actual water can be realized by the enrichment of Chlorella pyrenoidosa and XRF spectrometry.