An organic amine inhibitor was developed and evaluated. Experimental results showed that the organic amine inhibitor could decrease the surface tension to 50mN/m and had a little effect on the Zeta potential of clay. The inhibitor could effectively inhibit the dispersion of core and cuttings and had a lasting strong inhibition. The inhibitor had good compatibility with common drilling fluid, and it was useful to maintain drilling fluid stability under high temperature and could improve the filtration property of drilling fluid.