Electronic synapses have been widely designed to construct neuromorphic systems and artificial neural networks. However, neuromorphic systems are facing enormous challenges, with electronic synapses failing to rival biological synapses, whose connections form the unique learning and memory methods. In the biological learning methods, habituation, the most basic learning method, is the ability of animals to ignore innocuous stimuli to adapt to environmental changes. Mimicking habituation characteristic by synaptic device has important implications for intrducing biological learning into neuromorphic systems. In this paper, a synapse-like device based on memristor is designed to implement the habituation characteristic in Aplysia gill-withdrawal reflex. Firstly, a method for calculating the memristance of HP memristor by flux is improved. Based on this, synaptic device is designed using HP memristor as synapse. The habituation characteristic, including short-term habituation, long-term habituation, dishabituation and frequency-dependent habituation are implemented by the designed device. The realization of more complete habituation characteristic by unipolar pulses broadens the road for the study of neuromorphic systems based on synaptic devices.