Quantum linear amplifier is an important tool to enhance already-known quantum communications.It can be used to protect the quantum state against photon loss.However

the gain and the probability of success in amplification is quite low.To this point

we propose to use coherent displacement operations to enhance quantum linear amplifiers.We derive the exact threshold beyond which local displacement helps to enhance distillation.We apply our state transfer theorem and numerically evaluate the dependence of quantum linear amplifiers gain on the amounts of displacement.