The almost existing commercial HL7 interface engines apply the string array method which is run in the main memory to HL7 message parsing process. But, if the HL7 message is big, this method will be possible to cause the computer system to raise critical and fatal problems because a long string array can carry a too heavy load to the main memory and the processor. Therefore, the image and the multi-media data which are needed for the modern medical records could be limited to be included into a HL7 message because the size is usually too big in comparison with the main body of a HL7 message and in result, it make the size of the HL7 message expanded. The purpose of this study is to suggest a new HL7 interface algorithm which can solve this problem by the method of the 'Streaming Algorithm'. This new method for HL7 message parsing apply the character-stream object which process character by character between the main memory and hard disk device with the consequence that the processing load on main memory could be alleviated. The main functions of this new engine are generating, parsing, validating, browsing, sending, and receiving of message. And also, this can parse and generate XML-formated HL7 message. This engine had been practically tested in the Discharge Summary Information Exchange System between Kyungpook National University Hospital and Chonnam National University Hospital for the purpose of proofing its usability for a month. Overall, the preliminary results of this test is considered as good, but it is pointed out that some improvement is needed relating to the speed of parsing which was predicted because this engine partly used the memory of hard disk device instead of the main memory.