A test apparatus based on a DFDAU (Digital Flight Data Acquisition Unit), comprising: a simulation signal generation portion; and a test portion; wherein the simulation signal generation portion comprises: an input interface, which receives test data, the test data comprising data of aircraft condition or control command data; a simulation signal generation module (212, 300), which generates a simulation signal according to the test data; and an output interface, which is adapted to be connected to one end of one or more signal transmission devices to be tested and output the simulation signal; wherein the test portion comprises: a wiring extension device, which is used to form a gating wiring apparatus, and is adapted to be connected to the other end of the one or more signal transmission devices to be tested, and receives the simulation signal passing through the one or more signal transmission devices to be tested; the DFDAU, which is adapted to receive the simulation signal from the wiring extension device and obtain transmitted test data by converting the simulation signal from the wiring extension device into data of aircraft condition or control command data; and a comparison module, which is adapted to compare the test data and the transmitted test data. a simulation signal generation portion; and a test portion; wherein the simulation signal generation portion comprises: an input interface, which receives test data, the test data comprising data of aircraft condition or control command data; a simulation signal generation module (212, 300), which generates a simulation signal according to the test data; and an output interface, which is adapted to be connected to one end of one or more signal transmission devices to be tested and output the simulation signal; an input interface, which receives test data, the test data comprising data of aircraft condition or control command data; a simulation signal generation module (212, 300), which generates a simulation signal according to the test data; and an output interface, which is adapted to be connected to one end of one or more signal transmission devices to be tested and output the simulation signal; wherein the test portion comprises: a wiring extension device, which is used to form a gating wiring apparatus, and is adapted to be connected to the other end of the one or more signal transmission devices to be tested, and receives the simulation signal passing through the one or more signal transmission devices to be tested; the DFDAU, which is adapted to receive the simulation signal from the wiring extension device and obtain transmitted test data by converting the simulation signal from the wiring extension device into data of aircraft condition or control command data; and a comparison module, which is adapted to compare the test data and the transmitted test data. a wiring extension device, which is used to form a gating wiring apparatus, and is adapted to be connected to the other end of the one or more signal transmission devices to be tested, and receives the simulation signal passing through the one or more signal transmission devices to be tested; the DFDAU, which is adapted to receive the simulation signal from the wiring extension device and obtain transmitted test data by converting the simulation signal from the wiring extension device into data of aircraft condition or control command data; and a comparison module, which is adapted to compare the test data and the transmitted test data.