The present invention relates to a method for analyzing sterane-based compounds in a petroleum geological sample. According to the method, organic matters in a rock core sample are extracted with an organic solvent, and the extracted supernatant is directly analyzed through atmospheric pressure photoionization high resolution mass spectrometry (APPI FT-ICR MS). According to the present invention,with the method, the sample consumption is low, the sample preparation process is simple, the sample extraction time is short, and the extract can be directly subjected to atmospheric pressure photoionization high resolution mass spectrometry analysis without concentration and separation so as to avoid the compound loss caused during the separation; and the atmospheric pressure photoionization high resolution mass spectrometry analysis process is accurate and rapid, the sterane-based compound carbon number distribution range detected by the high resolution mass spectrometry has high reliability and high accuracy compared to the GC-MS results, and the method for analyzing the sterane-based compounds in the petroleum geological sample is expanded.