The invention relates to the technical field of well cementing and well completing for oil fields, in particular to a process for performing well drilling, well cementing and well completing at a low-pressure oil reservoir side. The process comprises the following steps of: A, reaming an original well bore after well drilling is completed at the low-pressure oil reservoir side; B, descending a well-completing casing pipe in the well bore after reaming is finished; C, descending a u-shaped pipe low-pressure well cementing device; D, descending a well-completing casing pipe provided with a cement basket; and E, cementing a well by adopting low-density cement. According to the invention, the well drilling and well cementing quality at the low-pressure oil reservoir side is increased, a fire flooding based oil reservoir exploiting effect is ensured, and the defects that the well cementing quality is poor and the exploitation and production of the oil reservoir are influenced because loss circulation is easily caused in a well cementing process of the prior art are overcome.