This paper investigates the transmission of regular incident waves interacting with a long rectangular floating breakwater with four mooring lines connected. We conduct two-dimensional physical model tests to measure the wave transmission coefficients, and investigate the effects of the relative width (W/L), the relative wave height (H/d) and the relative draft (s/d) on the wave dissipation coefficients. We also define the parameter(W/L)as a standard to deal with this experimental data and fit the formula based on normalized profiles.