Abstract: This study explores the applicability of X-ray fluorescence spectroscopy (XRF) technology in detecting heavy metals in farmland soil samples of different types and contamination levels. By selecting soil samples of various types and contamination levels, and using three single-wavelength or conventional energy-dispersive types of XRF devices tailored to different application scenarios, we quickly determined the concentrations of heavy metals such as lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), and nickel (Ni) in the tested soil samples, while analyzing the influence of soil properties on XRF detection results. At the same time, we conducted an applicability analysis of XRF technology in detecting heavy metals in polluted soils by comparing the results with those obtained from laboratory determinations using inductively coupled plasma mass spectrometry (ICP-MS). The results show that XRF detection of elements such as Pb, As, Cu, and Zn in the soil exhibited high accuracy and stability, with relative errors and relative standard deviations (RSD) mostly below 20%, which makes XRF suitable for rapid screening of these elements. However, the detection results for Cd, Cr, and Ni were significantly affected by matrix effects and spectral interferences in soils with high concentrations of iron (Fe), calcium (Ca), or organic matter, leading to considerable errors and impacting the accuracy of detection. In addition, the study evaluated the detection performance of the three XRF instruments in soils with different levels of contamination, revealing that the desktop single-wavelength instrument performed excellently in both low and high concentration samples, while the handheld single-wavelength and conventional handheld instruments were respectively suitable for high contamination scenarios and rapid screening of soil heavy metals. This study can provide a reference for the application of XRF technology in the rapid detection of heavy metals in soil.