We select CB and MB superconducting gravimeter (SG) stations with longer data length (2004-2020) and better observation quality, and use the oceanic Ni1o index (ONI) as the El Ni1o-southern oscillation (ENSO) index to assess the possible impact on SG observations at the interannual timescale (primarily 1-5 a). First, we remove the influences of instrument response, atmospheric tides, tidal effects, hydrological factors, and polar motion from the CB and MB observation series. Then, we apply the Morlet wavelet transform and cross-wavelet analysis to the data. The results show there is a significant correlation between SG observations and ONI, primarily at periods of approximately 1.5 a and 3 a. Specifically, gravity variations at CB station exhibit a negative correlation with ONI, while at MB station, the correlation is positive, with a time delay in the gravity observation relative to ONI. Furthermore, the ENSO effect on CB station is more pronounced than that on MB station, especially at about 3 a period, where ENSO shows a negative correlation with gravity variations at CB station. We hypothesize that this discrepancy is largely due to the different geographical locations of stations. However, more detailed quantitative studies are needed to further explore this relationship.