To address the issues of complex pretreatment and low sensitivity in traditional pesticide detection methods, an Au nanoparticles(AuNPs) composite terahertz(THz)metamaterial sensor based on laser fabrication is proposed. Periodic double U-shaped metamaterial arrays and AuNPs are prepared using picosecond laser direct writing and nanosecond laser scanning techniques, respectively. The combination of these two components enhances the interaction between THz waves and analytes. The simulation and experimental results demonstrate that the local electric field enhancement induced by AuNPs significantly improves the sensor's sensitivity, with the THz resonance intensity of the composite sensor being more than 12 times higher than that of the bare sensor. The experimental data further reveal that the detection limit of the sensor for chlorothalonil can reach 10 μg/mL.