The invention relates to a base line pile, and belongs to the field of instrument calibration. The large-size mobile base line pile is characterized by comprising a zero-bit mobile base line pile and a mobile base line target pile, wherein the zero-bit mobile base line pile and the mobile base line target pile are arranged at different points to form a section of base line; the zero-bit mobile base line pile comprises a pile base and four main body brackets arranged on the pile base; a two-dimensional horizontal linear adjusting mechanism, a two-dimensional rotating adjusting mechanism and granite positioning baffle blocks are arranged at the top end of each bracket; the granite positioning baffle blocks are arranged on each two adjusting mechanisms; the mobile base line target pile comprises a base line target pile base and a main body pile frame of a base line target; a horizontal pendulum mechanism is arranged on the main body pile frame of the base line target; and a practice target vertical to a horizontal end surface is arranged on the horizontal pendulum mechanism. According to the base line pile, instant putting, instant calibrating and instant correcting and verifying are achieved by respectively arranging the zero-bit mobile base line pile and the mobile base line target pile which are matched to form the base line; and the problem of a permanent base line field is solved.