In this paper, a novel flame retarded MCA-PA6 (PA6 incorporated with melamine cyanurate) resin was synthesized by in-situ polymerization. The synthetic product was characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), Fourier transform infrared spectroscope (FTIR), thermogravimetry analysis (TG), differential scanning calorimetry (DSC) and elemental analysis. The result showed that good dispersability were obtained in MCA-based PA6 prepared successfully. Meanwhile, the maximum mass loss rate appeared at about 450 °C and the residual char increased from 1.2 wt% to 3.2 wt% at 500 °C due to the existence of MCA.This research revealed MCA-PA6 owned a good thermal stability, hence there was potential flame retardance.