A robot for testing lower limb performance of a spacesuit includes a pressure maintaining box, an air circulation component, an air cooling unit, heat radiating hose components, and two mechanical legs. The air cooling unit is connected with the pressure maintaining box; the air circulation component is arranged in the pressure maintaining box; the mechanical legs are installed on the pressure maintaining box, and the heat radiating hose components are arranged in the mechanical legs; air in the pressure maintaining box is cooled through the air cooling unit and delivered into the heat radiating hose components through the air circulation component; each mechanical leg comprises a thigh, a knee joint component, a shank, an ankle joint component and a foot; the thigh is connected with the shank through the knee joint component; the shank is connected with the foot through the ankle joint component.