In this paper we propose a new decision analysis method combining quantitative logic and fuzzy soft set theory. Firstly, we transform a fuzzy information system into a fuzzy soft set, and then establish a formal language based on the fuzzy soft set, in which the parameters of fuzzy soft set are regarded as atomic formulas, some atomic formulas are connected by the logical connectives and then a logical formula is formed, and a implicative type of formula is interpreted as a soft decision rule (SDR). Secondly, various types of measures to evaluate the SDR are introduced and then the soft metric between two logical formulas is established. Thirdly, we apply the soft metric to the soft decision analysis, a SDR extraction algorithm for fuzzy decision information system and a corresponding recommendation algorithm are proposed. Finally, some attribute analysis examples, including the example as shown in rough sets and the practical credit card application example, are given to illustrate the newly proposed method and related concepts.

在本文中，我们提出了一种新的决策分析方法，将定量逻辑和模糊软集合理论相结合。首先将模糊信息系统转化为模糊软集，然后基于模糊软集建立形式化语言，其中将模糊软集的参数视为原子公式，一些原子公式通过逻辑连接词进行连接。然后形成逻辑公式，并将公式的隐含类型解释为软决策规则（SDR）。其次，介绍了各种评估SDR的方法，然后建立了两个逻辑公式之间的软度量。第三，将软度量应用于软决策分析，提出了模糊决策信息系统的SDR提取算法和相应的推荐算法。最后，