This paper chose the best fertilizing plan by grey decision analysis study.

In order to solve the problem about eliminating the subjective influence of human begin on the calculation of weigh,we give the water quality of Songbei wetland by using grey statistic decision analysis in this article.

Introducing the grey decision-making theory in the optimization of constructional parameters,the problem to transform multi-object optimization including the rates of ore recovery,undiluted ore recovery and rock drop-in into a single-object optimization was successfully solved.

The paper introduces the way of applying information entropy method to ascertain the indexes weights, researches the basic principles of grey decision-making, analyses the influence factors of building construction programs biding evaluation and builds the mathematic model.

With biodiversity, caterpillar population density and control cost as indices, optimal inoculating frequency and dosage were determined based on grey decision-making method.

In this paper, a new method for reasonably choosing drilling rig is provided according to the prin-ciple of grey decision of grey system theory and verified through example.

A single level grey decision making model,which is aimed at some existing problems on present decision of purchasing equipments,is proposed and its applications are shown with examples.