The pseudo-binary system LiIO3-Zn(IO3)2 has been investigated and its phase diag-ram determined by means of X-ray diffraction and DTA, using specimens prepared by solid state powder sintering method. A new phase, the formula of which can be written as LiZn(IO3)3, has been found to exist in single phase within a wide range of composi-tions. It is an ionic conductor and has remarkable SHG effect as determined by the powder method. The lattice paremeters of the compound LiZn(IO3)3 have been determined by a computer programme, using the powder diffraction data. It is found that the compound belongs to orthorhombic system with a = 8.081?, b = 8.729?, c = 11.595?, z = 4.