The invention provides an indoor and outdoor distinguishing method based on an LTE signal, and belongs to the technical field of the signal processing. The method comprises the following steps: firstly discretely selecting a plurality of reference nodes from indoor and outdoor, performing LTE signal collection on the reference points, and recording one LTE signal per second in the collection duration; endowing a label for each reference point, wherein the label comprises a geographic location of the reference point and the indoor and outdoor stage information; acquiring RSRP values and ECI ofa main service cell and an adjacent cell in the LTE signal, and accomplishing the establishment of the location fingerprint map Radio Map by combining the indoor and outdoor states of the signal in the label; training the Radio Map by utilizing a support vector machine algorithm to obtain an indoor-outdoor distinguishing model; and finally taking the to-be-distinguished RSRP vector as the input ofthe indoor and outdoor distinguishing model, wherein the output of the model is the indoor and outdoor distinguishing result. The problem that the indoor and outdoor distinguishing precision is low in the existing positioning technology is solved, and the indoor and outdoor distinguishing method can be used for indoor and outdoor distinguishing and positioning.