The invention relates to a hydro-thermal coordination considering unit operation mode decision-making method, which mainly comprises a unit annual operation mode decision-making support system, and is characterized in that the unit annual operation mode decision-making support system adopts a client/server mode, the whole system is composed of a database server, a calculation server, a client man-machine interface and the like, a database server, an application program server and a calculation server of software are firstly configured, the system provides a function of user management and authority management at the same time, and each user contains one or more roles. The beneficial effects are that a function of computer compilation for maintenance plans is realized, annual plans, monthly plans and daily plans of the unit maintenance capacity are calculated out, data analysis is performed according to data of the system, and a corresponding visual output result can be provided according to user requirements, thereby not only being capable of assisting the professional personnel to perform arrangement on a power generation plan and a maintenance plan, but further improving the accuracy of a calculation result and the work efficiency.