According to similarity theory, a towing experiment was conducted on the octagonal integrated mast to research on its hydrodynamic characteristics. The experiment measured the pressure on the surface of the mast, and analyzed the regularities of the average pressure coefficient changing with the Reynolds number, regularities of distribution of the average and fluctuating pressure coefficients in the axial and circumferential directions of the mast, and regularities of Strouhal number changing with Reynolds number and attack angle ,etc. The result shows that the average pressure coefficient tends to be stable with the increasing of the Reynolds number, and it distributes uniformly in the axial direction but changes greatly in the circumferential direction. Conclusions of the experiment play an important role in providing reference for the design of enclosed integrated mast.