The formula of high temperature tolerant and solids free weak gelling drilling fluid was: seawater,0.5% NaOH,0.5% Na2CO3,1% VIS-H,0.5% high temperature stabilizer SPD,3% KCl,1% polyamine UHIB,3% polymerization alcohols JLX-C,3% fluid loss agent RS-1 and 5% acid-soluble reservoir protection agent JQWY.The density of drilling fluid was aggravated to 1.2 g/cm3by sodium formate.The results of property evaluation showed that the high temperature stability of drilling fluid was good and the viscosity was of 34095 mPa · s with low rotate speed 0.3 r/min after rolling 16 h at 160℃.The lubricity and inhibitory of drilling fluid was good with 0.083 adhesion coefficient at 90℃,90.28% rolling recovery rate and 90.59% anti-clay-swelling rate.The damage of drilling fluid to reservoir greatly reduced after reservoir protective agent JQWY added and API filtration decreased to 2.6 mL.The filter cake could be easily removed by breaking gel agent JPC-LV on completion and the core recovery of permeability reached 97.8% which met the requirements of hydrocarbon reservoir development in high temperature horizontal well.