In view of the special requirements for cementing slurry in natural gas hydrate drilling, a new low-temperature and low-density cementing slurry formula was obtained with a number of experiments, the composition is 100% class-G oil well cement + 15% floating beads + 10%～15% micro silicon + 8% superfine slag + 1% defoaming agent + 0.5% fluid loss additive + 2.5% dispersant + 2% silane coupling agent + 5.6%～6% sodium metasilicate anhydrous + 8%～8.5% calcium chloride + 0.3% triethanolamine + 1% sodium chloride with 70% water-solid ratio. The slurry system can meet the cementing requirements of natural gas hydrate drilling in density, thickening time, compressive strength, rheology and bleeding at low temperature.