Abstract: More and more polycrystalline diamond compact (PDC) bits are used in oil well drilling, but their performance in the soft and hard rock interbeded formation is not ideal, premature failure occurs frequently. A new PDC bit design is presented to optimize its performance in the multi-interbeded formation, by modifying the pattern of cutting elements on conventional PDC bit. A new PDC bit made based on the design achieved desired results in field drilling, and in comparison with roller cone bit, it shows its advantage over higher ROP, longer service life and more footage, etc., and it’s beneficial for speeding up oilfield development and cutting down the drilling cost.