[Objective]The application cycle of the kelp in chemical industry would be prolonged based on the realization of its large scale storage.[Method]The pieces of kelp with different sizes were conserved in 2% formaldehyde solution in order to investigate the influence on the content and viscosity of alginate.[Results]In 2% formaldehyde solution,the content and viscosity of alginate in the large pieces of kelp were significantly higher than in the small pieces of one.The chemical reagent could accelerate the re...