The invention relates to a drilling process for deep hole machining for a hard material. A pre-drilling process is carried out at first, a pre-drilling bit is chosen to carry out pre-drilling on hole positions of a product, and during a pre-drilling process, tool setting is carried out at first, a pre-drilled hole with a depth of 0.5mm is machined for all the hole positions after the tool setting, foundations of the machined hole positions are moved by 0.5mm up and down after the operation is completed, the operation is repeated for many times, depths of 1-4mm, of the pre-drilled holes, are guaranteed, and pre-drilling operation is completed. The drilling process disclosed by the invention has the characteristics of avoiding breakage of the drilling bit, reducing a wear degree of the drilling bit and then lowering a production cost, omitting a wire wrapping process and then greatly increasing a machining speed of drilling, avoiding different hole diameters and then ensuring accuracy of the product, avoiding offset of the hole positions, and reducing consumption of the drilling bit and then prolonging the service life of the drilling bit, and the like.