Abstract: Based on field data of nutrients observed in Laizhou Bay during June,August,October and September,2013,distribution and seasonal variations of dissolved inorganic nitrogen and phosphorus in Laizhou Bay were analyzed in the present study.The results showed that DIN and PO4-P concentrations both presented significant seasonal differences in Laizhou bay,2013.And the DIN and PO4-P values peaked in August during our investigations,which were mainly influenced by the terrestrial input,even the DIN concentration over 50% of survey stations exceeded the fourth class of seawater quality standard.Followed by nutrient values in autumn,approximate 45% of investigating stations with DIN levels exceeded the fourth class of seawater quality standard.Whereas the DIN and PO4-P values performed the minimum in June,only 31.25% of stations with DIN concentrations over the fourth class of seawater quality standard.As for PO4-P concentration,it satisfied the first class of seawater quality standard during the four cruises.Generally,the N/P ratios of the four investigations were in high value,indicating that the phytoplankton growth in Laizhou Bay was potentially limited by phosphorus in 2013.