In this paper the authors treat of the application of Z-80 computer system in the variable head flowrate standard device, and give a minute description of the design of hardware and software. Good agreement is foung between the result obtained by the variable head and the result obtained by the ordinary constant head flowrate standard device to calibrate the electro-magnetic flowmeter. The results of the experiments confirm the good operational performance of the variabl head flowmeter standard device and the Z-80 computer system.