Abstract: This paper has discussed the mutual influcene of magnetic needles of magnetic variometers of various components, the variations of various components of geomagnetic field, and the effect of the incident angle of recording light on recordings.From this,it is considered that the deployment of a set of magnetic variometers should satisfy the following three criteria:(l)the mutual magnetostatic effect of magnetic needles of magnetic variometers of various components is small, and the effect of a working magnetic needle on any other magnetic needle is lower than the recording resolution of the magnetic variometer at this component;(2) the state function of magnetic variometers of various components is stable> their directional ability is strong;(3)the linear recording magnetic photographic graphs with relatively high precision can be produced.In view of that the present deployment of magnetic variometers falls short of these three criteria, this paper has presents a new deployment plan, which can satisfy the three criteria.