The low-solid drilling fluid is one of the most suitable drilling fluids for wireline core drilling； however， its poor anti-collapse and borehole cleaning capabilities hinder the application of wireline coring drilling in complex formations. The effects of nano-iron tetroxide， nano-boron nitride， nano-titanium dioxide， multi-wall carbon nanotubes and nano-silica on the rheological properties and filtration properties of low-solid drilling fluids were analyzed through experimental research. The results showed that： nano-iron tetroxide， multi-walled carbon nanotubes and nano-boron nitride had obvious effects on the performance of low-solid drilling fluids； furthermore， they can increase the viscosity and improve shear force. Then， the influence of the combination of the above three nanomaterials on the performance of the low-solid drilling fluid was analyzed by orthogonal experiments to obtain the optimized formulation of the composite nano-low-solid drilling fluid system with excellent performance： 3% sodium bentonite + 0.5% CMC-HV + 0.3% nano ferric oxide + 0.9% nanoboron nitride + 0.9% multi-walled carbon nanotubes. Finally， the mechanism of nanomaterials to improve the performance of low-solid drilling fluids is analyzed.