The present invention relates to a method for generating a decision tree using an inference engine in a ubiquitous environment. In the method, a data table for a data event set is generated based on information collected by at least one sensor. Subsequently, a weight value of the data event set is established, and an entropy is calculated based on the established weight value (here, the entropy is a scale for classifying the information collected by the sensor into respective classes). In addition, the decision tree for the collected information is formed based on the calculated entropy.