A laboratory facility to measure and calculate the point spread function (PSF) and the optic transfer function (OTF) of seawater is described. The PSF and OTF are important parameters for predicting light propagation and imaging system performance. An image transmission method for measuring the PSF is discussed and the 1 D and 2 D PSF curves for various scattering water path lengths are presented. The OTF are also calculated by FFT from the data of PSF. Some results are shown, which agree with the theory.