Abstract By analyzing the geomagnetic data noise and baseline value changes at Yingcheng station, various factors affecting data quality and deficiencies in station construction are explored. The results show that: 1) The interference of Wuhan subway operation is the primary factor affecting the geomagnetic background noise. 2) The noise of proton vector observation is mainly affected by the air temperature, the higher the temperature, the higher the noise. 3) The large annual temperature difference and high humidity in the recording room cause the baseline value to drift, and the observation data have many sudden jumps. 4) Instrument failure, greening operation and production activities may also reduce data quality.