Non-metallic pipelines are widely used in the construction of underground pipe networks. As one of the main detection methods of underground public facilities, the ground penetrating radar method is often used in the detection of underground non-metallic pipelines. Due to the weak echo signal of non-metallic pipelines, complex underground structures, and difficulty in accurately estimating wave velocity in the detection process, radar detection imaging and positioning have become a problem. In response to the above questions, the wave velocity estimation and echo signal processing methods suitable for buried non-metallic pipelines are studied, the spatial frequency domain interpolation imaging and binarized positioning algorithms are proposed, the feasibility of the imaging positioning method is verified by numerical simulation, and the field tests of non-metallic pipelines buried at 0.400m、0.600m and 1.100m are carried out. The experimental results show that the proposed method can effectively eliminate the hyperbolic effect, and the imaging positioning errors in the detection area are 0.006m、0.006m and 0.012m, respectively, which meet the positioning requirements of buried non-metallic pipelines. The research results can provide technical support for the imaging and positioning of buried non-metallic pipelines and are conducive to improving the detection accuracy of ground penetrating radar on underground non-metallic pipelines.