Abstract: An amplitude limited regenerative ¹⁴N NQR probe has been designed and built with field effect transistors. It has a frequency range of 1-5 MHz and a rf.amplitude range of 0.5-4 Vpp. In order to obtain a digital record system for NQR spectral lines, a microprocessor Z-80 is used to construct a phase sensitive detection system. By connecting this digital PSD system to the probe circuit through a signal processing channel, a regenerative ¹⁴N NQR spectrometer with microprocessor is constructed. The ¹⁴N NQR spectral lines of some compounds as hexa-methylenetetramine, sodium nitrite, urea etc. have been observed at room temperature and 77K with the spectrometer. The experiment results show that the s/n racio of NQR spectrometer with microprocessor is twice as large as one without microprocessor. Additionally, this instrument may provide a convenience for the further processing data.