The invention discloses a surgical navigation system and method based on an AR (augmented reality) technique. The surgical navigation system comprises a scanning device, a processor, a dynamic positioning acquisition device and an AR glasses, the scanning device scans a patient to obtain scanning image data and transmits the scanning image data to the processor before an operation is performed, the processor receives the scanning image data and generates a three-dimensional analog image of the patient, the dynamic positioning acquisition device acquires a positioning image and first real-time dynamic data of the patient in a coordinate system of the dynamic positioning acquisition device in the operation process and is used for acquiring second real-time dynamic data of the AR glasses in the coordinate system of the dynamic positioning acquisition device and transmitting the second real-time dynamic data to the processor, the processor generates a three-dimensional navigation image according to the three-dimensional analog image, the positioning image, the first real-time dynamic data and the second real-time dynamic data and transmits the three-dimensional navigation image to the AR glasses, the AR glasses receives and displays the three-dimensional navigation image. The surgical navigation system can dynamically display operation processes in the AR glasses, and the surgical navigation system and the patient are accurately overlaid in the AR glasses.