In this study, the instability behavior of angled pipelines conveying fluid is investigated by using three-dimensional finite element method. Several parameters that affect the dynamic characteristic have been studied extensively such as pipe lengths ratio, diameters ratio, frame angle, inlet fluid velocity, inlet fluid pressure, and pipe thickness. Taking into account the Coriolis force, force that conforms fluid to the curvature, and axial tension forces; the natural frequency of an angled pipeline fixed in both ends is studied. The derived element matrices include the mass, stiffness, contradictory and damping. The study found that increasing the obtuse angle leads to decrease the frame critical fluid velocity. For each formed pipeline angle, there was an optimal frame diameters ratio that gives maximum inlet critical velocity of flowing fluid. A relatively small increase in frame frequency is obtained when increasing the inlet fluid pressure. Besides that, there was a perfect pipe thickness for each fluid flow velocity that gives rise to get the extremely dynamic characteristic.