Some new experimental results carried out in a manifold circular pipe for liquidmetal MHD (Magneto-hydro-dynamic ) fluid flow were presemed in this article. Thevelocity distributions were measured at the center plane of cross section of the jointof the manifold pipe. The instabilities of vortex street were observed in the crosssection of the pipe. An expression formula of three--dimensional (3D) additional MHDpressure drop due to the manifold junction was obtained. 2D MHD effects and effectof non-fully developed flow on the experiment results were also discussed.