Molecular biology technologies have been widely used in aquatic animal disease diagnosis and molecular pathology studies, which require high quality of nucleic acid. However, how to preserve sample quality at normal temperature is rarely investigated. In this study, we compared the preserving effect of RNA in the tissues of shrimp Litopenaeus vannamei stored in different preservation solutions at normal temperature to find one preservation solution that can be used at normal temperature and long-distance transportation. Saturated solutions of ammonium sulfate and ammonium acetate in a serial of solvents with different ethanol concentrations were used to preserve shrimp tissues. The results showed that ammonium acetate has higher solubility in ethanol solution than ammonium sulfate. The molarity of ammonium ion of ammonium acetate is steadier in 0−80% ethanol. Ammonium acetate penetrates into the tissue of intact shrimp faster and reaches a higher concentration than ammonium sulfate does. RNA with better integrity, higher copies, and longer half-life period was achieved in the tissue preserved in more than 70% ethanol, saturated ammonium sulfate in the solvent of 50% and 70% ethanol, saturated ammonium acetate in the solvent of 50% ethanol. These results suggest that the saturated ammonium acetate in 50% ethanol as the solvent (pH=6.0) can be used as sample preserving solution to preserve RNA in shrimp tissues at normal temperature.