In order to improve the thermal conductivity and flame retardancy of coatings for electronic components，a nano filler（MF@BNNS）with both thermal conductivity and flame retardancy was prepared by using boron nitride nanosheets（BNNS）as thermal conductive unit and melamine formaldehyde resin（MF）as embedding agent. Thermal conductivity and flame retardant waterborne coatings was prepared by using MF@BNNS，waterborne polyurethane resin，poly-isocyanates and related additives. The microscopic morphologies of BNNS，MF@BNNS and char layer were investigated using scanning electron microscopy（SEM）. The structures of BNNS and MF@BNNS were characterized by Fourier transform infrared spectroscopy（FT-IR）. The thermal conductivity and flame retard as well as smoke suppression properties of the coating were studied by a hot wire thermal conductivity meter and a cone calorimeter（MCC）. The results showed that BNNS modified by MF could effectivelyenhance the thermal conductivity and flame retardancy. When MF@BNNS accounted for 2. 0%of the total amount of component A，the thermal conductivity increased to 0. 212 W/（m·K）， which was 35. 90% and 11. 58% higher than that of the blank sample and PCB. Meanwhile， the peak heat release rate（PHRR），total heat release rate（THR），peak smoke release rate（SPR）and total smoke release rate（TSP）of the coating decreased by 15. 21%，25. 91%，45. 07% and 88. 94%，respectively. The developed product not only solved the problem ofsingle performance of traditional fillers，but also overcome the problems of difficult dispersionand easy aggregation of BN nanoplates in polymer coatings，which had greatly promoted itsapplication in the field of electrical and electronic heat management.