Command style can be divided into concentrating command and dispersing command based on the concentrating degree of command power. This paper explores a new method of command style decision making analysis based on the fuzzy rough sets and fuzzy reasoning. Firstly, the factors, including command and control measures and information guarantee level, that have an effect on the command style are analyzed. The knowledge discovery method of the command style is studied and given based on the theory of fuzzy rough sets. Then, by means of the obtained fuzzy reasoning rules, the quantity decision making conclusion of command style can be obtained by the Mamdani fuzzy reasoning algorithm with multiple inputs and rules. Finally, a reasoning system based on the fuzzy logic tool box of matlab7.0 is established. Through deducing by this system, three kinds of simulation conclusions that are accordant with the subjective judgments of military experts are obtained. This simulation system can be brought into the operation decision making support system.