Abstract: Based on Literature in recent years of Bit Hydraulics at home and abroad, this paper addresses the latest developments of hydraulic parameters of PDC bits, bottom flow field and the progress of hydraulic optimization, proposing research problems and future research directions. Analysis shows that optimization of hydraulic parameters of PDC bits tend to use higher displacement and lower pumping pressure; the bits bottom flow field simulation Has been gradually shifting from two-dimensional, single-nozzle flow numerical simulation developed to a three-dimensional, rotating, non-symmetric multi-nozzle flow numerical simulation; bits bottom flow field has organically combined with experiments; PDC bits bottom flow field simulation use water as the medium, leaving the influence of flow field by the viscosity of drilling fluid, bottom debris and the bottom temperature out of account. The Hydraulics Research on PDC bit still at a qualitative stage. the quantification of PDC bit hydraulics is the focus of future research work.