PDC（聚晶金刚石复合片）钻头的强度对钻进效果有着决定性影响。通过大量现场钻进结果表明，90%以上钻头因钻头体超前损坏和切削齿失效等因素导致钻头报废，造成了大量浪费。因此，有必要开展PDC钻头切削载荷和钻头强度等方面的研究，其具有重要的理论和实际意义。 论文通过对已失效钻头分析，总结出钻头失效类型有钻头体失效和切削齿失效，并讨论了影响失效的主要因素，在此基础上选择了两种典型的地质PDC钻头作为研究对象。其次，从钻头切削齿与岩石之间的相互作用关系展开分析，在岩石力学和类比金属切削力学基础上，导出了切削齿单元体模型剪切面和切削面上应力公式。最后，采用PRO/ENGINEER软件建立了典型地质PDC钻头的三维实体模型，通过对模型进行有限元分析，发现切削齿切削深度越深，切削齿上应力越小，但切削齿的磨损速度加快；当其它参数不变时，岩石力学参数越大，切削齿上应力越大；当切削深度一定时，切削面积与弧长越大，切削齿上应力越小。根据分析的结果对钻头切削齿形状进行改进，并对改进后的钻头进行有限元分析，分析结果表明PDC钻头的力学性能得到了改善。本文的研究为其它种类的地质PDC钻头的设计提供了一定得参考。

The strength of PDC bit have a decisive influence to drilling effect. A large amount of onspot drilling results indicates that above 90% bit is scrapped because of early shatter of aiguille body or failure of tooth, which causes a mass of waste. So it is necessary to study cutting load,strength and other aspects of the PDC bit which have important theoretical and practical significance. Firstly, according to analysis on invalidity bit, invalidity types of bit are summarized, they are bit body invalidity and cutting teeth invalidity. And also the main factors of invalidity are studied. Based on the study above, two types of typical geological PDC bit are selected as research objects. Secondly, the relation between bit cutting and rock is analized, based on the rock mechanics and cutting mechanics, then the stress formulas on shear plane and cutting plane of the bit cutting units model are derived. Finally, according to PRO/ENGINEER software, a typical geological PDC solid model is established, accroding to finite element analysis on the model, it is obtained that the deeper the cutting depth of cutting teeth, the lower the stress on cutting teeth, but wear rate accelerates; when other parameters are invariant, the greater the rock mechanics parameters, the greater the stess on cutting teeth; when the depth is invariant, as the cutting area becomes biger and arc-length becomes longer, the stress on the cutting teeth becomes lower. Then according to the analysis results, cutting teeth shape of bit is developed, and finite element analysis on bit developed is carried on. The results show that mechanical properties of PDC bit are improved. And reference for design of other PDC bit is provided through the study on geological PDC bit.