A review concerning the current situation of weather modifications based on the theory of natural cybernetics is given. The authors proposed that the direct as well as the inverse problems for weather modifications should be investigated. Based on a case study, the optimal controlling problem for weather modification operation is discussed. The results show that natural cybernetics is a good theoretical framework to instruct weather modifications. Not only observations of natural weather precipitation processes should be strengthened and numerical models to simulate them should be developed, but also the inverse problem, i.e., the optimal controlling problem for the weather modification should be studied. It is not only to consider the potentiality of rain enhancement by cloud seeding, but also need to investigate the temporal evolution and macro-micro-structures of precipitation cloud in the relevant weather system.