The invention relates to an amino-acid recyclable fracturing fluid thickener and a preparation method thereof. The thickener is prepared from the following components in percentage by mass: 7%-10% of modified xanthan gum, 5%-7% of gellan gum, 0.5%-1% of a clay stabilizer, 0.6%-1% of a regulator, 0.3%-0.7 of a protective agent, 10% of polyethylene glycol, 1%-2% of a dispersing agent and the balance of water. The thickener has the characteristics of being good in compatibility, low in frictional resistance, good in proppant carrying capacity, few in residues, small in formation damage, high in salt resistance, relatively high in instant solubility and the like; the viscosity can be increased; the thickener can be applied to a high-temperature deep well. The thickener does not need a lot of additive when a fracturing fluid is prepared; infinite cyclic utilization of a common fracturing fluid (or an acidizing and fracturing fluid) is achieved; the fracturing fluid has the characteristics of being simple in formula, convenient to operate, low in cost, continuous to mix and clean in production; water is saved.