In research on the suitability of the Water Quality Network Planning (WQNP) in China,the na-tional territory is divided into some water quality units according to the river systems.Then the categories of unitsare determined as a basis of WQNP by using a principal component cluster variety method.Within the units in thesame category,water quality parameters are classified by the fuzzy collective cluster method to determine the densi-ty of water quality networks.Meanwhile,sampling frequencies for each parameter are analysed to provide the con-cerned guidance.