The piezoelectric tuning fork is widely used in industries, and its frequency characteristic is the key parameter determining its engineering application of the piezoelectric tuning fork. In order to accurately test the frequency characteristics of the piezoelectric tuning fork, this paper take tuning fork material level meter as the research object,which is commonly used in industries.The detecting system based on ARM9 frequency characteristics measurement system is designed,displaying the nature frequency of the fork,so as to judge whether the piezoelectric tuning fork meets the engineering requirements,improving the accuracy and efficiency.