Firstly, the operations of extension and transition in soft set over the universe U and the parameter E are proposed and some related properties are derived. Secondly, it is proved that the quotient soft set with the operations of combination and focusing is a domain-free information algebra. Moreover, the algebra is also compact if the set of all possible parameters is finite. Finally, an algorithm of decision making in term of the model of domain-free information algebra is presented and a corresponding example is provided to show that this model can be successfully applied to many problems. A comparison between the proposed algorithm and Cagman's uni-int decision making is illustrated in the end.