Abstract: The Quasi-Static Model (QSM) solution of vertical incident longitudinal waves in plate-like adhesive structure was studied. Under the condition that the bonding interface was simplified as a Quasi-Static Model, the expressions of the reflection and transmission coefficients of vertical incident longitudinal waves in plate-like adhesive structure with perfectly connected interfaces and the same material for upper and lower substrates were derived. The Quasi-Static Model and the exact solutions of longitudinal waves were compared with each other to explain the applicable conditions of the Quasi-Static Model. The influences of the changes of the normal stiffness coefficient and relative mass of the interface on the reflection and transmission characteristics of longitudinal waves were analyzed. The results indicate that at certain frequencies, the reflection coefficient of longitudinal waves reduces to a stable value, while the transmission coefficient increases to a stable value with the increase of the stiffness coefficient or the relative mass of the interface. The research results could provide a theoretical guide for the detection of bonding structure by longitudinal wave vertical incident.