Based on data acquired from April 7 to November 23, 2005 in Modern Yellow River Delta, preliminary study on the relationships between soil electrical conductivity and soil suction of 30cm depth were carried out with eighteen field observation wells for soil moisture and soil salt monitoring. The results indicated that the correlation between soil electrical conductivity and soil suction of 30cm depth was not statistically significant from April 7 to November 23, 2005. During the period of April 7 to June 6, 2005 (i.e., the initial stages of plant growth, seedtime of crops), only the correlation between soil electrical conductivity and soil suction of 30cm depth at DZ05, DZ16 and DZ17 were statistically significant, positive linear correlation, and the correlation between soil electrical conductivity and soil suction of 30cm depth at DZ08, DZ13 and DZ15 could be modeled by curve estimation. During the period of September 30 to November 23, 2005 (i.e., the final phase of plant growth), the correlation between soil electrical conductivity and soil suction of 30cm depth at DZ01, DZ02, DZ04, DZ06, DZ10, DZ12, DZ14, DZ15 and DZ18 could be modeled by curve estimation, and the correlation between soil electrical conductivity and soil suction of 30cm depth at DZ07, DZ16 were statistically significant, negative linear correlation, and the correlation between soil electrical conductivity and soil suction of 30cm depth at DZ03 was statistically significant, positive linear correlation. Thus it could be seen that the final phase of plant growth was the best period for studying the relationships between soil electrical conductivity and soil suction collected from field on-the-spot observation in Modern Yellow River Delta.