The invention provides an automatic monitoring instrument working platform of a shield tunnel. The automatic monitoring instrument working platform comprises a horizontal main frame and inclined struts. A left supporting plate and a right supporting plate of the horizontal main frame are fixedly connected together through a first cross rod, a second cross rod and a third cross rod, wherein the first cross rod, the second cross rod and the third cross rod are parallel to one another. Trays are fixedly arranged on the upper surfaces of the second and third cross rods, and the outer end of the left supporting plate and the outer end of the right supporting plate are fixedly connected with the upper ends of the inclined struts respectively. The working platform is simple in structure, the structural dead weight is reduced to the utmost extent on the basis of meeting stiffness and stability requirements, and transportation and installation are convenient. The available space is sufficient, and the working platform can meet the requirements for arranging an automatic monitoring instrument and accessory communication and power supply equipment. Leveling is convenient, and the environmental suitability is high. The monitoring instrument working platform is flexible in installation position, the working platform can be quickly leveled through the inclined struts, the working efficiency is high, and the environmental suitability is high. The installation has no damage to a shield tunnel structure, and when the working platform is matched with a special shield chute, punching does not need to be conducted on the tunnel structure, so that it is really achieved that no damage is caused to the structure during installation.