Abstract: An experiment has been performed in National Key Laboratory of Bubble Physics and Natural Circulation（BPNC）,Nuclear Power Institute of China（NPIC） to study the effect of the main operating parameters and the inlet restriction pressure-drop on the oscillation among channels. The experimental results show that the increasing of the temperature of feed water increases the oscillation amplitude , but it is not of linear relationship; the increasing of steam pressure decreases the oscillation amplitude, but there is no effect on the oscillation period; the increasing of feed water flow rate decreases the oscillation amplitude and increases the oscillation frequency; the increasing of the input power improves the stability of secondary side of test section; and the increasing of the restriction pressure-drop improves the stability of test section.