Newcastle disease virus (NDV) belongs to the Paramyxoviridae family and has had a great impact on the poultry industry. In the past, NDV strains were generally pathogenic only to fowls, but goose paramyxovirus (goose-origin APVM-1) is highly infectious to waterfowl, and, thus, there have been frequent outbreaks in China since 1997. In this study three pairs of specific primers were designed to detect the virulence of different NDV and goose-origin APVM-1 isolates and to differentiate between NDV and goose-origin APVM-1 using multiplex reverse transcription–polymerase chain reaction (RT-PCR). Pathogenicity tests were performed to confirm multiplex RT-PCR results. Data from our study indicate that multiplex RT-PCR is a convenient, low-cost, and effective technique for rapid identification. Twenty-six viral isolates of NDV and four goose-origin APVM-1 were analyzed, and we found that the VII genotype of NDV is the most prevalent type in South China and that it is not closely related to viral strains common to Europe.