结合时差法超声波流量计的基本原理,提出了一种多脉冲法的设计方案｡选用了时间数字转换芯片TDC-GP2､MSP430F155单片机和ispLSI1032 CPLD等芯片,介绍了时差法超声波流量计的测量原理,阐述了测量系统的组成及软硬件设计,详细分析了ispLSI1032内部各组成模块和设计原理;得到了较好的实验结果,测量结果波动的峰峰值不超过2 ns,2 s内可以跟上流速变化,精度高于1%｡ New Transit-time Ultrasonic Flowmeter MENG Hua,YAN Fei,LI Ming-wei (School of Electronic and Information Engineering, Dalian University of Technology, Dalian 116023,China) Abstract:A multi-pulse transit-time technique based on the basic principle of transittime ultrasonic flowmeter was presented. Time-to-digital converter TDC-GP2,MCU MSP430F155 and CPLD ispLSI1032 were selected.The principle of transmit-time method was introduced. The structure of the measurement system and the realization of both software and hardware were detailed narrated. Modules inside the ispLSI1032 are described in details. The good result was obtained. The pick-to-pick time of measuring result is less than 2 ns, while catching up the flow in 2 s with 1% precision. Key words:ultrasonic; flowmeter; multi-pulse transit-time; TDC-GP2