The invention relates to a control method for differential settlements in a hydropower project. The method comprises the following steps that 1, a foundation is strengthened in design through a pouring pile, a jet grouting pile, a vibroflotation pile, an impermeable wall and a curtain grouting measure; 2, a release sluice adopts an integrated sluice pier structure, and a plurality of copper water stops are arranged between the upstream and the downstream of the release sluice as well as between gaps of the release sluice; and 3, in the construction sequence, the lower half foundations of a right side sluice dam and a gravitational power plant factory building are poured firstly, then the filling of a sandy gravel foundation is conducted and a left side sluice dam foundation is poured on the sandy gravel foundation, then the upper half foundation of the right side sluice dam is poured, and the upper half foundation of the gravitational power plant factory building is poured at last. According to the control method, the uneven differential settlements caused by many aspects such as the construction, the design and the arrangement of the building on the sluice dam with a deep covering layer are eradicated, and the base stress of adjacent dam sections is made to stay the same as far as possible; and each construction stage is controlled, and the differential settlements of adjacent buildings meet the design requirements.