Traditional floor plan construction suffers problems of high trajectory energy consumption and large cumulative error.Therefore, this paper proposed a new construction method without using sensors but useing Wi-Fi signal to sense the movement of people to construct an accessible path structure so as to draw the final indoor plan.The experimental results show that the method of using CSI to detect the path structure in indoor environment is more accurate and lowcost, and the precision of the constructed floorplan achieves an average of 87%, and the structure of floorplan is complete enough to be suitable for indoor location service.