The invention provides plate strip straightening equipment comprising a rack, a main pressing device, a work roller group, a supporting roller group, a roller seat, an upper inclined wedge adjusting device, a transmission mechanism, an upper box body and a lower box body. The main pressing device comprises four main hydraulic cylinders and the four main hydraulic cylinders are used for enabling the upper work roller group to generate different pressing amounts at an operation side and a transmission side. The upper inclined wedge adjusting device is arranged along the axially vertical direction of the upper working roller group. The upper inclined wedge adjusting device comprises a first upper inclined wedge, a first lower inclined wedge and a first oil cylinder. The first oil cylinder is used for driving the first upper inclined wedge and the first lower inclined wedge to move along a radial direction of the upper work roller group so as to increase the pressing amount of the upper work roller group. The plate strip straightening equipment can eliminate edge wave and middle wave defects of a plate strip. The invention further provides a precision adjusting method of the plate strip straightening equipment.