Abstract: 8 dominant species were chosen based on the living and dead foraminifera analyses from 106 surface samples, taken from the intertidal zone and shallow sea on the west of Bohai Bay. The vertical distribution features of the dead foraminifera depending on the water depth (altitude) were studied, and a quantitative relation of different foraminiferal species between vertical assemblage zones and sea level and geoenvironment was discussed. The results show that the indicative scope of the foraminiferal species and assemblages defines its sensitivity and precision as an indicator of geoenvironment and sea level (altitude) change. The marine index of the foraminifera and its relativity with altitude were constructed. The relative sea level curve of the study area was obtained by a case study. It has further proved that foraminifera can be an indicator for the sea level and geoenvironmental reconstruction.