The invention provides a coastal multi-source multi-load coordination control system and method considering sea water desalination. The coastal multi-source multi-load coordination control system comprises a control center, a new energy power station, an energy storage device, sea water desalination facilities and conventional loads. The control center is used for formulating an optimal day-aheadplan and an optimal intra-day plan, and controlling the new energy storage device and the seawater desalination facilities to be executed so as to carry out coordination control according to acquiredoperation data and meteorological data. Thus, the optimized regulation and control path of the multi-source multi-load seawater desalination process can be accurately provided, the characteristics ofthe energy storage technology are fully utilized, the coastal controllable load and energy storage are adjusted by taking energy storage adjustment as a main principle and controllable load adjustmentas an auxiliary principle so as to track a renewable energy power generation curve, and the consumption requirement of renewable energy in coastal regions is met.