Spatial distribution patterns of nitrate nitrogen and ammonia nitrogen were studied in the tidal marsh soils of the Yellow River Delta by geo-statistical methods.The results showed that the NO₃^--N and NH₄⁺-N contents had significant horizontal variability in different soil layers,which was mainly correlated with their active physical transport characteristics caused by the better water conditions in the tidal marsh.The horizontal distribution of NO₃^--N in topsoil displayed significant spatial structure,which can be best fitted with Gaussian model and had moderate spatial correlation.The natural structure factors had significant effects on the spatial variability,while the effects of random factors were relatively low.The maximum spatial variability of NO₃^--N in topsoil was observed in the direction extending towards the low tidal marsh,showing a great effect by the ebbs and flows of tide.The spatial distribution patterns of NO₃^--N in topsoil were significant.The lowNO₃^--N contents in topsoil were generally observed on the sites close to low tidal marshes,while the high values appeared on the edges of the study area.This study indicated that micro-physiognomy characteristics and tidal micro-domain physical disturbance were the two most important random factors inducing spatial heterogeneity,while water and salinity conditions,soil types and tidal circulation were three important structure factors.