Fractal theory has been established for more than 20 years. Taking the fractal theory into solving geotechnical engineering problems has been gradually perfected. This paper concludes several common methods within the fractal theory research. Meanwhile, sums up the research results of the predecessors during the correlation field. At last, illustrates the application of fractal theory within the geotechnical engineering problems' research in detail, such as the microstructure fractal of soil, the fractal dimension on the joint surface, the relation between fractal dimension and rock quality coefficient(RQD), fractal damage and fractal fracture, and application of fractal theory(mechanics) to related geotechnical engineering.