Long term storage experiment was conducted to analyze the storage performance of hydroxylammonium nitrate (HAN) hydrogel which was made from polyvinyl (PVA) as gel agent. There was precipitation liquid which contains HAN under the open system, while under sealed condition, this phenomenon of precipitation liquid did not occur and the combustion performance of HAN hydrogel did not change significantly. Results show that HAN hydrogel should be storied under sealed condition and the temperature should not exceed 40 ℃.