Abstract: Based on the research of the topological optimization method with level set, the non-probability reliability constraint of interval parameters structure was analyzed. Through deducing and transforming the finite element formula, the suppositional safety factor form with non-probability reliability information is proposed, by which the non-probability reliability constraints are dealt with explicitly. This method was simple in form and quick to perform, and avoids complicated iteration operations. The feasibility and validity of this method is verified through comparing the data and topological figures of examples.