High-precision measurement of geomagnetic field is important in many applications, including geology and geomagnetic-matching navigation. A single atomic magnetometer cannot simultaneously realize high-precision measurements of the magnitude and direction of geomagnetic field. A promising solution of magnetic field vector measurement is a type of atomic magnetometer based on coherent population trapping (CPT) effect. Firstly, the principle of measuring magnetic field vector based on the CPT effect is introduced. Then, two types of methods for measuring magnetic field vector with or without auxiliary coils are discussed, and three key technologies for measuring magnetic field vector based on CPT effect are discussed, including accurate measurement of gradient magnetic field, continuous real-time measurement of magnetic field vector, closed-loop control of measurement system, and interference suppression. Finally, the application prospects of CPT-based magnetic field vector measurement methods are explored from three aspects: calibration and compensation of heading error, reduction of the effect of magnetic field gradient with micro-electromechanical system atomic vapor cell technology, and elimination of optical power fluctuations with an optical power compensation algorithm.