The polyamide 6 powder was prepared by the liquid phase method, and then mixed with hexagonal boron nitride (h-BN) in a high-pressure homogenizer for micron-level mixing, and finally the composite material is obtained by hot pressing. The thermal conductivity of composites was as high as 1.73 W/(m•K). The results showed that the dispersion of h-BN in the matrix was well and there was no obvious agglomeration in the composite from the scanning electron microscope. Differential scanning calorimetry and X-ray diffraction results showed that h-BN affects the crystalline of polyamide 6 and the thermal stability of the composites was improved. The composite is expected to be used in high thermal conductivity functional plastics.