Hydropower as renewable, clean and cheap energy occupies a considerable share in power energy production. With more and more hydropower stations being established and involved in joint operation, long-term joint scheduling of hydropower station group (LJSHSG) has become a challenging constrained optimization problem, because of its characteristics of high dimension, nonlinearity and coupling. In order to deal with this problem effectively, the partition parameter adaptation differential evolution (PPADE) is put forward based on success-history based adaptive differential evolution (SHADE). PPADE uses a new mutation strategy “current-to-pbest/U-lp”, which is improved with relaxing the index restrained condition and linearly decreased region of control parameter p with large initial value based on “current-to-pbest/1” to prevent premature convergence. In addition, the partition parameter adaptation divides the population in descending order according to fitness and entry set into C partition so that each population partition corresponds to a partition of entry set for enhancing exploitation by faster and better boot parameter update in PPADE. Then numerical experiments of 10 benchmark functions in high dimension and low dimension have been done, it shows that PPADE with above improvement has stable convergence and high efficiency. With the PPADE compared with other improved DE algorithms in the LJSHSG problem of four completed hydropower stations, Xiluodu, Xiangjiaba, Three Gorges and Gezhouba, in the upper reaches of the Yangtze River, PPADE increases the power production compared to SHADE, EPSDE, CoDE and LSHADE in average best benefit by 9.06, 17.09, 35.69, 69.67 × 108 kWh in wet year. It demonstrates that PPADE has stable and efficient convergence to be a useful and reliable tool for LJSHSG problem. Then two hydropower stations under construction, Wudongde and Baihetan, are add into consideration to analysis compensation benefit of hydropower station group (HSG). The increments of the power production in the situation with Wudongde and Baihetan over without Wudongde and Baihetan on power production of four completed hydropower stations are 106.44 × 108 kWh, and decrements on deserted water of four completed hydropower stations are 14.22% in wet year. The result shows that joint operation of six hydropower stations and can significantly improve the power generation by reducing the spill water in four completed hydropower stations because of the increased regulation capacity from two hydropower stations under construction in the upper reaches of the Yangtze River.