Abstract: In recent years, China's port construction exhibits the development trend of large scale and deep water, and many ports are not the same type of seawall construction. Riprap construction of sloping breakwaters in open waters endures many complex factors from the external environment. Especially, coastal regions have distribution of deep and soft soil layers. With the increase in riprap amount and breakwater size, the real-time monitoring of settlement deformation is critical to control construction speed and project quality. According to the project situation and the characteristics of GPS technique, a real-time monitoring method for foundation settlement of sloping breakwater is proposed, including manufacture, laying and observation of subsidence monitoring equipments. The application of engineering example shows that the proposed method is suitable for the complex environment of riprap construction, and the settlement monitoring information can provide reliable basis for adjusting the intensity of riprap so as to ensure the safety of sloping breakwaters.