At present， the measurement of mud filter loss in the drilling site or in the mud laboratory is mainly based on the traditional manual measurement，with cumbersome measurement procedures， large reading error， and low work efficiency. For this reason， the research and development of the automatic measuring instrument for mud filtration has been carried out. LSZ-1 automatic instrument for medium and low pressure mud filtration has been developed through technical breakthrough in structural design， software development， sensor optimization， new filter material development， etc. Through laboratory tests， key technological breakthroughs such as automatic measurement of mud filtration loss， data storage and wireless transmission， and automatic cleaning of the device have been realized. The successful development of this instrument can provide technical support for the implementation of intelligent deep drilling engineering in the future， effectively reduce labor intensity， improve data measurement reliability and work efficiency， and is the core technical equipment of drilling information and automation.