To quickly and accurately evaluate the risk of ochratoxin A (OTA) pollution in dairy products, a method to detect fungi capable of producing OTA in dairy products was developed using gene probe scanning technology. According to the elucidated biosynthesis pathway of OTA, the halogenase gene related to OTA production was selected to design degenerate primers to establish a polymerase chain reaction (PCR) method for the detection of OTA-producing fungi. One OTAproducing strain (Aspergillus ochraceus) and five strains not able to produce OTA (Aspergillus cristatus, Aspergillus flavus, Fusarium moniliforme, Issatchenkia terricola, and Saccharomyces cerevisiae) were selected to test the PCR method. It was found that DNA from the OTA-producing strain but not the non-OTA producers could be amplified by PCR. Moreover, this method had high accuracy and sensitivity for detecting polluted dairy products.