Abstract: Probes, liquid phase chips and methods for detecting PIK3CA gene mutations are provided, wherein the liquid chips for detecting PIK3CA gene mutations mainly comprise: microspheres coupled with probes; primers used for amplifying target sequences with exon 9 and/or exon 20. The liquid chips and methods for detecting PIK3CA gene mutations are useful for detecting the sites containing mutations of the PIK3CA gene with relatively high frequency simultaneously, and also are useful for detecting the exon 9 and exon 20 separately or simultaneously. The detection methods have identical reaction conditions of detection, good specificity of detection, high sensitivity, above 90% accuracy, and short time of detection.