A paper-based surface-enhanced Raman scattering (SERS) sensor that combined the excellent performance of three-dimensional (3D) dendritic gold (DAu) matrix and the selective adsorption ability of biomimetic recognition polymer (BRP) has been constructed for ultrasensitive detection of thiram. The 3D DAu structure decorated on cellulosic matrix provides predominant SERS performance and chemical stability for the analytical platform. Compared with two-dimensional (2D) SERS platforms, it can get efficient utilization of 3D laser excitation volume to achieve optimal SERS enhancement. BRP membranes for the specific recognition and enrichment of thiram were prepared by bulk polymerization. And the urchin-like nanoparticles (UNPs) with rich cutting-edge structure were decorated in the BRP to provide sufficient “hot spots”. In the region where DAU was close to UNPS, the synergistic SERS enhancement was generated through particle plasmon coupling. And the whole structure of the composite multilayer provides multiple SERS enhancement for thiram detection. The SERS response of the sensor toward thiram showed excellent correlation during the range of 1 × 10−10 to 1 × 10−7 mol·L−1 with the detection limits as low as 2.75 × 10−11 mol·L−1. The test results of selectivity, reproducibility, and accuracy indicated that the paper-based DAu/BRP (UNPs) sensor possessed potential applications in pesticides analytical and other related fields.