The invention relates to a macro-axis submerged high-temperature molten salt pump comprehensive test detection device which comprises a test pump and a molten salt tank; the test pump is located in the molten salt tank; a loop pipe inlet is formed in the molten salt tank; an output port of the test pump is connected with the loop pipe inlet through a loop pipe; a pressure gauge, a flowmeter, a check valve, a flow regulating valve and a service valve are arranged on the loop pipe; and a pressure gauge and a liquid level meter are arranged on the molten salt tank. A high temperature condition test is realized; a pump test device and a valve test device are combined so that a device occupied area and operation energy consumption are reduced; and molten salt pump and valve test conditions and working conditions are unified so that precise evaluation is provided for pump and valve performance under the high temperature condition. A monitoring sensor is arranged in a key position and monitors the operating stability of the test devices and to-be-tested equipment, the operating stability of a tested object can be evaluated with the combination of a performance evaluation result, and safe operation of test equipment can be ensured.