Slope rotation positioning control system and method for excavator

The invention relates to slope rotation positioning control of an excavator, and aims to solve the problem that an upper vehicle body automatically rotates downwards when an existing excavator works on a slope. The invention provides a slope rotation positioning control system and method for an excavator, and the method comprises the steps: obtaining the pressure of two main oil ports of a rotation motor and the rotation speed of an upper vehicle body when there is no rotation operation; the gravity gyroscopic moment direction of the upper vehicle body is determined according to the pressure difference of two main oil ports of the rotary motor; and the electric control rotary main valve is controlled to enable the motor rotary torque direction of the upper vehicle body under the action of the rotary motor to be opposite to the gravity rotary torque direction and enable the rotary speed of the upper vehicle body to be zero. When the excavator does not rotate on a slope, the electronic control rotating main val