The invention discloses whole-oil synthetic base drilling fluid which mainly comprises following components: base liquid 100 parts, histosol 2-5 parts, viscosity increaser 0.5-3 parts, filtrate reducer 2-5 parts, wetting agent 0.5-2 parts, emulsifier 1-3 parts, calcium oxide 0.5 part and weighting agent 27-180 parts. The invention has the advantages that firstly, the rheological property is good and the plastic viscosity is low, secondly, the anti-temperature performance is good and anti-temperature can reach 150 DEG C, thirdly, the invention is provided with good water loss wall building performance with API filter loss content<5ml and high temperature and high pressure filter loss content <= 10 ml, fourthly, the anti-pollution ability is strong and the anti-poor soil ability and the anti-water invasion ability respectively reach 20%, and fifthly, reservoir has good protective effects and the permeability recovery value is over 85%.