An infrared horizon sensor is one of the important equipment of a satellite attitude control system. And yet, an infrared thermistor detector is the key unit of the infrared horizon sensor. Its quality is directly related to the performance and reliability of the infrared horizon sensor. With the continuous development of modern space technology, the next generation of infrared horizon sensors have an urgent demand for high-reliability long linear array infrared thermistor detectors. In recent years, researchers have made a great breakthrough in synthesizing Mn-Co-Ni-O (MCN) thin films by a novel chemical solution deposition (CSD) method. Since the compactness of MCN films is much better than that of sintering ceramic materials, it is possible to use it to fabricate long life and high-reliability infrared thermistor detectors. In addition, the similarity between the fabrication technology of MCN thin film detectors and that of microelectronic devices has provided the basis of fabricating long linear thermistor detector arrays. High quality MCN thin film infrared thermistor detectors are fabricated by microelectronic processes. Some key processes such as etching and annealing are studied. These new technologies and methods are of significance both to the application of thin film infrared thermistor detectors in the fields of space observation and remote sensing of our country and to the improvement of reliability and lifetime of horizon sensors.