The invention provides an automatic data deleting method based on DICOM. The method comprises the following steps: step 1, detecting the capacity of a disk space, carrying out step 2 if the available space of the disk space is smaller than a first threshold valve, and otherwise, enabling the system to operate normally; step 2, accessing a database, searching data records confirming to deleting conditions and acquiring the storage path of a data file corresponding to the searched data records in the disk space; step 3, carrying out deleting operation on the data file stored in the disk space according to the storage path; step 4, detecting the capacity of the disk space again, stopping data deleting operation if the capacity of the available space is greater than a second threshold valve, and otherwise, carrying out step 2 again. When the technical scheme provided by the invention is used for deleting data in medical equipment, the situation that data is deleted mistakenly or is not deleted completely can be avoided.