Scientific and technological intermediary can boost the trans for mation from science and technology into productivity. A right, objective, and scientific evaluation can raise the competitiveness of science and technology and develop evaluation for scientific and technological intermediary fast. The competitiveness of scientific and technological intermediary organizations is studied from the two parts, such as operation and method, evaluation principles are put out, the evaluating index system is built and a three-tier BP net model for the competitiveness evaluation of scientific and technological intermediary organizations is applied.