Abstract: 【Objective】 This study aimed to isolate and identify the pathogenic fungi and their secondary metabolites led to sugarcane moldiness， and to investigate the changes of the physiological and biochemical indexes of sugarcane after pathogen infection， which could provide theoretical reference for improving postharvest storage preservation quality. 【Method】 Taking the moldy sugarcane as experimental materials， pathogenic fungi producing toxins were isolated and identified using molecular technology. The pathogenic fungi were cultured 14 d in vitro using potato-yeast-sucrose （PYS） liquid medium； the pathogenic fungi and their secondary metabolites were analyzed by high performance liquid chromatography and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. Sugarcane stems were infected with spore suspension of 10 µL Apiospora pathogen at 10⁴ CFU/mL for durations of 0， 1， 2， 3， 4， 5， 6， 7， 8， and 9 d，with sterile distilled water as control. The effects of different treatments on physiological and biochemical indexes of sugarcane such as activities of phenylalanine ammonia-lyase （PAL）， superoxide dismutase （SOD）， peroxidase （POD） ， and polyphenol oxidase （PPO）， and contents of titratable acidity and soluble solids were determined. 【Result】 In the moldy sugarcanes， the pathogens that produced toxins were isolated and named LX1911 strain， and it was identified as Apiospora arundinis. The content of 3-nitropropionic acid toxin in the culture filtrate was determined to be 18.43 μg/mL by high performance liquid chromatography. Fifteen volatile compounds produced by LX1911 strain were identified using headspace solid phase microextraction coupled with gas chromatography-mass spectrometry， including alcohols， esters， hydrocarbons， phenols. The content of alcohols was 5.768 µg/mL， among which the content of mellein was 20.291 µg/mL. Physiological and biochemical experimental results showed that，compared with control，， sugarcane in expenmental group exhibited increase in PAL and SOD activities. Notably， during the first 3 d， the control group exhibited higher titratable acidity and soluble solids content than the experimental group. 【Conclusion】 The pathogen causing moldiness of sugarcane is identified as Apiospora arundinis， and it also marks the first time to find mellein in the metabolites of Apiospora arundinis.