Abstract: An ultrasonic sensing method and an ultrasonic sensing device are provided. The ultrasonic sensing device includes a microprocessor, a signal-driving module and a transducer module. The microprocessor generates a first driving signal with a first frequency to the signal-driving module. The signal-driving module drives the transducer module to emit a first sensing signal to a target object in response to the first driving signal. Then, a first echo signal received by the transducer is transmitted to the microprocessor to calculate a first time of flight. In a similar manner, a second time of flight is obtained based on a second driving signal with a second frequency. The microprocessor determines a final time of flight according to the first time of flight or the second time of flight.