Abstract: Using traditional methods to analyse the safety of industrial projects, safety benefit and value can only reflect the safety situation of system partially, the effect of analytical results on improving the safety situation of system is limited and its application is not satisfied. By introducing the theory of value analysis, safety benefit-value simultaneous equations and optimization criteria were built. Integrating the only area chart, the function area method (FAM) was finally developed. By applying this method to engineering projects, the only area chart and curves were obtained based on the technical parameters of projects, and the safety value and cost of projects were greatly improved.