The invention discloses a seawater silicate drilling fluid which comprises fresh water bentonite slurry 25 parts, seawater 75 parts, filtration-loss-reducing agent 2.0 to 5.0 parts, potassium chloride 5 to 7 parts, lubricant 1 to 2 parts, stabilizer 2 to 4 parts, and weighting agent 65 to 70 parts. The drilling fluid has the advantages of (1) good fluidity; (2) good wall building property, low HTHP filtration loss equal to or less than 15 ml, and thin mud cake; (3) high contamination resistance and (3) high poor soil invasion resistance (up to 15%); (4) good inhibition and large cuttings roller recovery larger than 85%; and (5) high lubricity and low friction coefficient.