Provided is a question answering system with respect to a natural language question and a method thereof. The question answering system includes a candidate answer generating unit configured to extract a document mapped to an input natural language question, and generate candidate answers with respect to the natural language question from the extracted document, a text entailment recognizing unit configured to generate a text entailment recognition result representing a degree of association between multiple evidence sentences including the generated candidate answers and the natural language question, a list generating unit configured to generate a candidate answer list including the multiple evidence sentences in high association degree order on the basis of the text entailment recognition result, and an output unit configured to output the generated candidate answer list as a search result with respect to the natural language question.