Well Jin-3 is in the Northeast of China. Aimed at Shahezi Fm of compact mudstone, soft-hard interbedded formations, strong abrasive, low ROP and short service life of bit, through improving matrix formula, taking wear resistant surface set natural diamond and impregnated synthetic diamond inlaid teeth by hot pressing as cutting teeth, optimizing the cutting structure of the bit, simulating and optimizing the bit hydraulic structure by CFD software, the new mix setting diamond bit （NR826M）was developed. The total footage reached 784.69m in well Jin-3 with only 3 this newly designed bits, the average ROP was 1.05m/h, the highest footage of one bit was 295m; the service life and the ROP were 6.5 times and 1.5 times higher than those of rock bit respectively, which shortens drilling cycle for 40 days with the reduction of drilling cost, and provides more choices for bit selection in the similar strata of this area.