The invention discloses a rocket launching combustion gas flow impact simulation test device, which comprises a test bed plate, a test rack, a test plate, a tapered head guide rod, an engine and a fixed support, wherein the upper surface of the test bed plate is provided with a bar-shaped sliding groove; the bottom end of the test rack is arranged in the sliding groove; the test bed plate and the test rack are fixedly connected through a bolt; the test plate is fixed on the test rack; the tapered head guide rod is provided with a tapered head front end and a flat head tail end, the tapered head front end abuts against the outer side surface of the test plate, and the flat head tail end is connected with a nozzle of the engine; the inner side surface of the test plate is fixedly connected with a sensor; and the engine is fixed on the fixed support. The rocket launching combustion gas flow impact simulation test device has the outstanding advantages of short production cycle, short test time, simple structure, low cost and the like.