Abstract: Taking the Ninglang M5.7 earthquake on June 24, 2012 as an example, and combining with the precursor reflections of other earthquakes in Northwestern Yunnan, the characteristics of anomalous information recorded by precursor instruments at Yongsheng, Lijiang, Yunlong, Chuxiong, Midu and Eryuan stations before the earthquake were comprehensively analyzed. It is found that these anomalies not only have clear short-impending indicators and obvious synchronization, but also have complete short-term change processes. According to these anomalous forms, anomalous amplitudes, anomalous duration and causes, the anomalous characteristics can be basically summarized into three types:short-term anomalies of pre-earthquake continuity and post-earthquake recovery; impending earthquake anomalies of synchronism; short-term and impending earthquake anomalies of "pre-earthquake disturbance".