Abstract: Y-waveguide is widely used in the integrated optics, and it is important to know its specifications, among which the beam-splitting ratio and insertion loss are the most critical parameters. The measurement setups and methods for the two parameters are introduced. As for the beam-splitting ratio, the output luminous power for two tail fibers of Y-waveguide was measured respectively by using two sources with wavelengths at 1300nm and 1550, and the primary factors which affected the measurement were analyzed and the uncertainty was evaluated after working out the beam-splitting ratio according to the formula. As for the insertion loss, the measurement setup was built up based on the measurement principle, and the factors which affected the measurement of the insertion loss were theoretically analyzed.