Thermopile infrared (IR) sensors based on the thermoelectric effect are widely applied in industrial and civil fields. Researchers urgently need to develop a technique for in situ online extraction of the sensor's thermal parameters, in order to allow for better analysis of the sensor's performance and to improve its structure. In this work, a pulse-voltage-based self-test method is proposed. The pulse voltage can be generated easily, and only a few data points are required, with simple data processing. The measured results are close to the theoretical values and results from the constant current method proposed in another paper, thus indicating that our method is effective and accurate. In addition, it has strong significance for array testing.