The invention discloses a fishway inlet fish collection system side dispersed water charging system arranging method and belongs to the field of fishway engineering. According to the fishway inlet fish collection system side dispersed water charging system arranging method, a side dispersed water charging type is adopted, the possible problem of sediment accumulation caused by water charging for the bottom of a fish collection canal is avoided, the method is particularly suitable for construction of a fishway fish collection system on a silt-laden river, and long-term stable operation of the system can be guaranteed; the vertical scale of the fish collection system is not increased, the structural stability is improved, and the system can be arranged on a power station tailwater platform easily; and a water charging mode and relevant measures proposed in the design provided by the invention are simple, engineering construction is facilitated, and the universal reference is high.