Underground fluid observation plays an important role in earthquake prediction research and earthquake tracking. In this paper, the observation data and characteristics of anomalies from underground fluid around the epicenter of Maduo M_S7.4 earthquake on May 22, 2021 were systematically analyzed, and the prediction process before the earthquake was reviewed. the results show that there exist 5 anomalies within 500km of Maduo epicenter, and 4 of them are short-term anomalies, mainly occurring 2~3 months before the earthquake. the anomalies are evenly distributed in space, but mainly located in the northeast and southwest of Maduo epicenter, displaying an overall migration characteristic from the periphery to the epicenter. There exists a good similarity between Maduo M_S7.4 earthquake and Qinghai Yushu M_S7.1 earthquake in 2010 in terms of anomaly characteristics and stress loading. the results of this paper added more earthquake cases for areas with low seismic monitoring ability, and have certain reference for improving the understanding of precursory anomalies of underground fluid of strong earthquakes and for determining future earthquake situation trend.