The invention discloses a method for aligning a base line of a two-dimensional rotating table, and the method uses radar equipment and low-cost equipment to realize rapid alignment of the base line ofthe two-dimensional rotating table under the environment of field testing. Mainly used auxiliary measuring equipment are GPS machine equipment, a geomagnetic sensor and a gradienter. The enforcementmode of the method includes the steps that firstly, the radar equipment is fixed to the rotating table, and the rotating table is leveled; secondly, a reference point is set beyond the distance being400m from the rotating table, an angle reflector is placed, and the longitude, latitude and height of the rotating table position and the reference point position are measured by GPS; thirdly, the rotating table is adjusted to align the forward-looking direction of a radar base with the position of the reference point, and thus the base line of the rotating table coincides with a reference base line; and fourthly, the azimuth angle and pitch angle of the rotating table base line are calculated and fused with a measurement value of the geomagnetic sensor to obtain a final measurement value of the rotating table base line. According to the method for aligning the base line of the two-dimensional rotating table, under the condition of field testing, the angle measurement characteristics of the radar equipment are fully utilized, the low-cost and easily purchased auxiliary equipment is adopted, and the simple, convenient and fast method for aligning the base line of the rotating table is achieved.