Ultrasonic measurements at high magnetic field and low temperature necessitate ultra-fast excitations, ultra-high dynamic range of duty-cycle adjustments, as well as real-time, precise and automatic analysis. This paper proposes a dual-mode ultrasonic measurement system, which means the capability of carrying out acoustic measurements in both pulsed and static high magnetic field with low temperature. Based on the “counter-delay-chain” series structure and adaptive jitter compensation in the field-programmable-gate-array(FPGA), the timing control accuracy of 5 nanoseconds and the timing jitter below 160 picoseconds are realized for high-resolution excitation generation and precise sampling window adjustment. The duty cycle adjustment achieves a high dynamic range from 0.23 ppb to 10 % to realize both pulsed field mode and static field mode (denoted as PF-mode and SF-mode) ultrasonic measurements. The independent sampling window adjustment reduces the data size by more than 80%, extends the maximum testing duration and reduces the analysis consuming. Combined with the automatic cross-correlation analysis method, this system can automatically carry out PF-mode tests with a repetition rate above 100 kHz and SF-mode tests for hours with sound velocity accuracy of 2%. Experiments have proved the reliability and feasibility of the system and revealed its application prospect in condensed matter physics experiments.