In July of 2008, in-situ measurement of erodibility for surficial sediment was conducted using a self-developed recirculating seawater flume on the tidal flat of the modern Yellow River delta. Selected physical-mechanical sediment properties were measured at the same time. The results show that the critical erosion shear stress of the surficial tidal sediments varies between 0.088 Pa and 0.254 Pa. The nonuniform erodibility of surficial tidal sediments causes pitting.