Integrated quantum memories that can synchronize of a large number of quantum computers are essential to build a quantum network to boost the information processing capability. Here, we propose to store optical quantum state into erbium doped lithium niobate (Er 3+ : LiNbO 3 ) micro-cavity by using electro-optic effect. The cavity frequency of Er 3+ : LiNbO 3 micro cavity can be shifted by an external electric field, which can be used to control the emission of photon echo by changing the resonance condition between cavity and collective atomic excitation. Our calculation shows that high efficiency and low noise performance is achievable for large detunings. Benefiting from the host lithium-niobate thin film, such a device can be controlled by on-chip electrodes and is easy to be integrated with other photonic devices of various functionalities, paving way of integrated quantum chips.