A low-voltage multi-frequency and amplitude mixed test source generating device is characterized by comprising a power frequency power source, a four-winding transformer, a sampling device, a random noise generator and a pulse generator. The low-voltage multi-frequency and amplitude mixed test source generating device has the advantages of being economical, feasible, high in flexibility, free of a complex signal generating device and capable of being widely applied to tests of transformers, mutual inductors and capacitors.