Single-photon counting technology has been used extensively in testing due to its powerful quantitative
performance for ultraweak luminescence intensity such as high time resolution and large dynamic range. However, some
negative factors limit its performance in practice. In this work, the methods for weak signal detection and self-fitting
noise suppression were applied to the signal processing in the single-photon counting system in which a photomultiplier
tube (PMT) was the photoelectric sensor. Firstly, the weak signal from PMT was amplified by two stage amplifiers and
subtracted by its means. And then the lost pluses were corrected by double discriminating voltages as different peaks'
circumscriptions. Lastly it was proposed to put program-controlled auto compensation function for self-adjusting ability
and high sensitivity. By these methods, the measure errors caused by narrow pulse interval and double-photons peak are
decreased whilst the counting efficiency is increased. It was demonstrated that the performance of the single-photon
counting system, in which signals were processed with the proposed methods, was enhanced and the system was more
flexible in terms of self-fitting measuring.