In practical applications, the fuel flowmeter will work in unsteady flow state, and the measurement performance of the flowmeter may change. Using the dynamic fuel flow standard device, the unsteady flow tests was performed on the Coriolis mass flowmeter and the volumetric scraper flowmeter. The influence of unsteady flow environment on the measurement results of the two kinds flowmeters is analyzed, and the use and calibration of recommendations are given.