For studying the statistical properties of characteristic quantities in noise signal, such as the amplitude of extreme, the amplituds of the rising edge and the falling edge, the interval between extreme points and the product value of the quantities,the background noise signal sequence values of photoelectric sensor in suspended particle counter are recorded by using the high-speed data acquisition card. The results show that the statistical distribution of these characteristic quantities match well with the form of the log-normal distribution, with natural number l used as the independent variable. The statistical distributions of characteristic quantities show a high degree of similar characteristics. Based on this statistical similarity the transform relationship between the independent variables corresponding to different characteristic quantities by power function can be derived. The similarity between statistical distribution functions of characteristic quantities can be understood as a kind of performance of statistical fractal characteristics for noise signal collections.