The invention discloses silty mudstone natural gas hydrate storage compound type drilling fluid, and relates to the field of natural gas hydrate exploitation. The drilling fluid is prepared from the following components: polyethylene glycol, sodium chloride, ethylene glycol, potassium chloride, potassium humate, potassium polyacrylate, xanthan gum, polyvinyl caprolactam, polyvinyl methyl ether, tetrahexyltrimethyl ammonium bromide and prepared water. The silty mudstone natural gas hydrate storage compound type drilling fluid can be used for silty mudstone natural gas hydrate storing and drilling, has the effects of resisting a low temperature, inhibiting and reducing the solid phase; a kinetic inhibitor and a synergist are added into the drilling fluid for compounding, so that relatively strong hydrate generation inhibition effect is achieved; and moreover, the drilling fluid is small in environmental harm by components, and has the advantages of being efficient, environmentally friendly, adopting cheap and easily available raw materials, and the like.