The invention discloses a method for sliding pressure curve deep optimization based on load zone distinguishing. A sliding pressure curve of a turbine under a certain back pressure is obtained through a control valve steam distribution optimization test, and then the running relation between the main steam pressure and the unit power under the certain back pressure is obtained. The method for deep optimization comprises the steps that when the back pressure of the unit changes, the unit power obtained after the back pressure changes is corrected to the power corresponding to the back pressure of the unit when the known sliding pressure curve changes through back pressure correction, and therefore the optimal main steam pressure under the changing back pressure condition is obtained. The corrected power corresponding to the back pressure of the unit when the known sliding pressure curve changes is used as the standard, the main steam pressure is adjusted corresponding to the known sliding pressure curve, in this way, the optimal sliding pressure curve can be obtained no matter how the back pressure of the unit changes, the economy of the unit is greatly improved, and the method is simple and easy to implement.