© 2017 Elsevier B.V. Liquid Bi has complex structure that a characteristic shoulder structure aside of the first peak exists both in structure factor and pair distribution function. To investigate origin of this complexity from atomic dynamics, we performed quasi-elastic neutron scattering measurements. A new procedure to reduce real-time and real-space functions from the dynamic structure factor obtained in momentum-transfer and energy-transfer space was introduced to prevent truncation errors in Fourier transforms. The reduced intermediate scattering functions and van Hove dynamical correlation functions reveal that the shoulder structure shows characteristic relaxation interpreted as process loosing double-layered structure based on Peierls distortion in liquid Bi. The robustness of the shoulder structure against temperature can be understood by metallic nature of the local structure.