The invention discloses a steering bearing shaft washer channel parameter measuring instrument and measuring method. The steering bearing shaft washer channel parameter measuring instrument is characterized in that a system support and a measuring platform are fixed on a system flat plate; a stepping motor, a ballscrew support, a first linear guideway, a second linear guideway and a grating scale are fixed on the system support; a sensor rack is fixed on the first linear guideway and the second linear guideway, and is connected with a slide block of a ballscrew and the grating scale; the motor is connected with the ballscrew through a shaft coupling and drives the ballscrew to rotate; a first sensor system, a second sensor system and a linear bearing are fixed on the sensor rack; a guide rod is connected with a positioning pressure head, and penetrates through the linear bearing to move up and down; and a pressure spring is arranged between the positioning pressure head and the linear bearing. For the steering bearing shaft washer channel parameter measuring instrument and measuring method, two radial sensors and one axial sensor are used to measure the size of a channel, so that digital measurement of the shaft washer channel parameter is realized; and the differential motion mode of a pair of sensors is used to measure, so that the measuring error caused by inaccurate left and right positioning of the shaft washer can be eliminated and measurement of the channel center distance can be realized at the same time.