Because light is scattered and absorbed by seawater, the images obtained underwater are always blurry after transmitted through a certain distance. The point spread function (PSF) and modulation transfer function (MTF) are important properties of seawater to predict underwater light propagation and underwater image quality. We describe the laboratory facilities to measure the PSF and MTF of water body by the image transmission method and the restoration methods of under- water blurred images. The measured results are given and compared with the theories. The blurred images of a bar target transmitted through different water paths are restored with the measured MTF using a Wiener filter. © 2001 Society of Photo-Optical Instrumentation Engineers.