The experiments aim to study the enrichment regularity of inorganic arsenic and total arsenic in kelp by analyzing the variation of inorganic and total arsenic in kelps which are from different maritime regions and different species during their growth.The content of inorganic arsenic is detected by HPLC-AFS,while the content of the total arsenic is examined by hydride atomic fluorescence spectrophotometry inGB/T 5009.11-2003.The results show that the enrichment in kelps of total arsenic displays an increase trend in growing season,whereas the content of inorganic arsenic is decreasing.The percentage of inorganic arsenic in total arsenic decreased from 1.36%-1.47%(March)to 0.41%-0.57%(July).The enrichment of inorganic and total arsenic varies from kelp to kelp even they are cultivated in the same maritime region,meanwhile,the same types of kelps have dramatically different contents of inorganic and total arsenic,which depends on the variety of maritime regions.Judging from the data,the contents of inorganic arsenic in all examined kelps are far below the MRL and will have no negative effects on food safety.The study provides relevant theory foundation for food safety and processing.