The measurement of bidirectional function Q is difficult in the case of Ⅱ waters, due to their high-scattering properties, and the HYDROLIGHT is used to simulate the Q value at the 440 nm wavelength with observation angles at the solar nadir angle. Then the effects of environment and water optical characters on Q value are analyzed. Results indicate that in shore and inland lakes of high-scattering waters, the influence of wind speed, scattering phase function, and other factors on the Q value decreases due to the increase in scattering time. So single albedo(W0) and solar zenith angle (θ) become the main influencing factors. With increasing depth, the effect of conditions such as boundary and incident light on the bidirectional function Q value becomes weaker and weaker until the effect disappears completely. In this case the Q value becomes the internal optical parameter that bears no relationship with the conditions of boundary and incident light. The main influencing factors W0, θ, and diffuse attenuation coefficient KLu of upwelling radiance are used to parameterize the Q value that can be expressed in two ways.