The indoor/outdoor call judgment method comprises the following steps. Firstly, to build an algorithm and indicator function for determining indoor/outdoor call by analyzing drive test data. Secondly, to retrieve the event log data to be judged by the method, and find the position of the retrieved event log data by means of geo-location tools. Thirdly, to determine whether the retrieved event log data are referring to a moving call, if “YES”, then the event log is determined to be referring to an outdoor call. Fourthly, to determine whether or not the event log data are referring to an Indoor call by using the pre-built algorithm and the indicator function. Users' behavior, Cell antenna module and signal strength difference are considered when building the algorithm and indicator function so as to increase the accuracy of the indoor/outdoor call judgment method.