ln an ultrasonic Doppler elfeet experiment, an abnormal signal from other ultrasonic sources wascollected by the local reeciver. 'To explain this phenomenon, firstly, two possible paths of the signals were hypothesized, and the corresponding physical models proposed. Experiments were then carried out respectively to verily the models. lt was proved that the abnormal signal in the experiment originated from the rellection olsound waves coming from adjacent ultrasonic wave sources through the ceiling and the ground. Finally , it was elarified that the loeal measured results would not be interfered by the adjacent experiments, by both of theory and experiment. lt demonstrates the paradigm of “ phenomenon-questions-conjecture-modeling- verification" in our experiment teaching to guide and inspire students to question and to solve problems. While explaining phenomena , students’ experimental thinking was trained and their problem-solving ability was improved.