Abstract: In the depression and waterlogging land of Hai River Plain where the groundwater depth to the surface is about 2～3m，the salt content in topsoil is less or equal to 50g／kg，and the relative height of landform is less or equal to 66cm，the primary and secondary relationships among some factors are considered by using the Path Analysis method．The results show that the topsoi1 salinity mainly depends on the salinity of bottom soi1 and micro-landform ，whereas the indirect effect of subsoil salinity on topsoil salinity through the bottom soil is the biggest one among all of six effects．