In order to analyze the correlation laws between fractal feature and equipments worn states

the software used to identification particles contours and to compute the fratcal dimension of the particles contours is programmed based on the computer. This paper presents the fractal parameter and its calculation method of the worn particles based on particles contours' chain code. Some worn experimental tests were carried out at the pin on disc experiments and the worn debris were sampled at varies running in stages. It is found that

when the subroutine be used to compute the particles' parameters

the change of the fratcal dimension of the worn debris is corresponded to the machine worn states at different running in stages. The results show that it is convenient to compute the fratcal dimension of the particles contours with this subroutine. The software offers effective and simple methods in researching the correlation law between fractal feature and equipments worn states.