The MWCNT-COOH and CTAB modified MMT were hybridized by the ultrasonic method, and the nylon 66/MMT/WMCNT composite was prepared by in-situ polymerization to study the effect of the introduction of MMT and MWCNT on the properties of nylon 66. A scanning electron micrograph of the composite cross-section shows that the CNTs were uniformly dispersed in the nylon 66 matrix. The XRD patterns show that the introduction of MMT and MWCNT-COOH caused the ratio of α1 and α2 of nanocomposites. The TGA results show that the heat resistance and residual carbon content of the composite material are improved. The mechanical properties of nanocomposites show that the mechanical properties of the material are improved relative to pure PA66.