The invention relates to a method for extracting needed and specific text information from a closed hospital information system (HIS) and inputting the information to another picture archiving and communication system (PACS) to be used for medical administration. Automatic transmission and exchange of the text information is finished through the procedures of setting a system hook, acquiring a course address, operating the system hook, outputting the text information, acquiring a cursor position, setting a window text and the like. The invention realizes the functions of automatic acquisition of information among different systems and automatic retransmission of information through extracting display information of a computer screen, meets the requirement of extracting the patient information of the HIS by the PACS, improves the working efficiency of the medical workers and reduces the probability of medical negligence and medical dispute due to patient information error caused by human negligence.