The invention discloses a method for detecting aldehydes in rice. According to the method, the method is realized by employing a headspace derived solid phase micro-extraction-gas chromatography-mass spectrometry method. The method comprises the following steps of: grinding a rice sample, adding the detected sample into a headspace bottle, introducing protective gas, inserting an extraction head into the headspace bottle filled with derivative liquid for deriving for 20 minutes, and inserting the extraction head into a headspace sample introduction bottle, wherein the extraction temperature is 40 DEG C, and the extraction time is 80 minutes; detecting in a gas chromatograph-mass spectrometer. The fineness and headspace derivatization conditions of the ground rice particles are optimized, so that newly generated aldehydes in the analysis process are avoided, and the accuracy of an experimental result is improved. According to the detection method, five steps of adsorbing derivative liquid of the extraction head, deriving and extracting the aldehydes, performing sample introduction, separating and measuring can be sequentially finished in a process, automation is realized, the operation is simple, the detection efficiency and accuracy are improved, and absolute quantification of nine aldehydes in rice is realized.