Structural design is subject to some unavoidable uncertainties in material and geometrical properties,loads,etc.To achieve the goal of harmony and balance between the structural safety and economy , the combination of structural reliability theory , in which uncertainties can be handled reasonably. and the advanced techniques for the optimization of structures becomes a natural choice of engineers. The optimization of structures based on reliability can make an optimum balance between safety and economy. and thus became the high goal of structural designers. In this paper. the techniques of probabilistic reliability-based on structural optimization are briefly reviewed in contents. methods and its relative theones. Some existing problems are discussed.