The content of this article is the application of enumeration com binatorics in economics. Xiaoping Deng, the great leader and chief designerof China, proposed that China’s fiscal revenue should quadruple.The authors are inspired to obtain the quadruple sequence,further researches its generating functions within the framework of the mathematical model, and give a unimodal conjecture related the quadruple sequence about the series, also it has been proven that this conjecture holds when 1 ≤ r ≤ 11. The research has both theoretical value and practical significance for combinatorics,mathematical analysis and economics.