The invention discloses a polyvinyl alcohol compound drilling fluid for natural gas hydrate (NGH) reservoir in a frozen soil area, and relates to the field of NGH exploitation. The drilling fluid comprises following components: polyvinyl alcohol, sodium chloride, methanol, glycol, sulfonated phenolic resin (SMP-2), potassium humate, xanthan gum, polyvinylpyrrolidone K-90, propylene glycol phenyl ether, polyvinyl methyl ether, and make-up water. The drilling fluid is suitable for NGH drill wells in a frozen soil layer, does not contain any solid phase, and is resistant to low temperature. The drilling fluid is compounded with a kinetic inhibitor and a synergist to inhibit the generation of hydrates. Moreover, the components of the drilling fluid are basically harmless to the environment, and the drilling fluid has the advantages that the efficiency is high, the environment is protected, and the raw materials are cheap and easily available.