The supply source of nutrients for the primary productivity at the coastal ocean is regarded as mainly river transportation from land. Particularly, river plays an important roll at the coastal ocean. The river water is influenced by the land use of the watershed. Therefore, we studied the relationships between the land use of watersheds and the marine nutrients in the river especially for the marine diatoms. The rivers studied were the Ohkawa River and the Nanakita River in northeast of Honshu Island in Japan. We sampled river water at 5 points in both rivers from June 2003 to April 2004. We focused nitrogen, phosphorus and silicon for the nutrients. TERRA/ASTER data observed from 2001 to 2004 were used to analyze the land use in the watersheds. Existing 50m resolutions digital elevation model (DEM) was used to analyze the land use about elevation. The areas of watersheds per each sampling point were produced and the land use of each watershed was calculated. Then we compared each the area ratio of land use and the concentrations of each nutrient. NH 4-N concentration of the Ohkawa River was correlated with the area ratio of pasture field, but the rest was not correlated each other. NH 4-N and NO 3-N concentration of the Nanakita River were correlated with some area ratios; especially those concentrations were strong correlated with the area ratio of urban area and golf course.