Realization of functional flexible artificial synapse is a significant step toward neuromorphic computing. Herein, a flexible artificial synapse based on ferroelectric tunnel junctions (FTJs) is demonstrated, using BiFeO₃ (BFO) thin film as the functional layer. The inorganic single crystalline FTJs grown on rigid perovskite substrates at high temperatures are integrated with the flexible plastic substrates, by using the water-soluble Sr₃Al₂O₆ (SAO) as the sacrificial layer and the following transfer. The transferred freestanding BFO thin film exhibits excellent ferroelectric properties. Moreover, the memristive properties and the brain-like synaptic learning performance of the flexible FTJs are investigated. The results show that multilevel resistance states were maintained well of the flexible artificial synapse, together with their stable synaptic learning properties. Our work indicates the promising opportunity of ferroelectric thin film based flexible synapse used in the future neuromorphic computing system.