It is an important technology to solve the problem of high-precision ore-controlled exploration and drilling for Small-diameter directional drilling. In view of the broad-spectrum adaptability of the PDC bit of the thin and soft interbedded small-diameter directional drilling construction of hard rock in the Lanling iron ore area, Through the optimization design of the crown shape of the drill bit, the blade arrangement, the PDC cutting tooth inlay welding angle, the hydraulic structure of the drill bit and the drill bit carcass, the Φ98mm directional drilling PDC bit was developed. After the application verification of three directional drilling holes in heterogeneous strata above medium hardness, PDC drill bits have achieved satisfactory results in impact damage resistance, wear resistance, drill bit life, etc., achieving the purpose of efficient rock crushing and continuous and stable directional directional drilling, and providing an effective solution for the design and manufacture of small-diameter directional drilling PDC bits.