In order to reduce the requirement of three-axis vector atomic magnetometers for the attitude control range of the motion platform， a scalar pump-probe atomic magnetometer with a smaller dead zone was selected for the vector atomic magnetometer based on the magnetic field rotation-modulation method. The improved vector atomic magnetometer had a smaller dead zone and had the potential to be used on a stationary or slow-moving platform. Firstly， the working principle of the vector atomic magnetometer based on the magnetic field rotation-modulation method was introduced. Secondly， the distribution of dead zones of the vector atomic magnetometers was analyzed when the scalar atomic magnetometer was selected as an Mx type optical pump magnetometer or a pump-probe type atomic magnetometer. Finally， the technical specifications of the three-axis atomic magnetometer with a small dead zone were validated near the geomagnetic field. When the three-axis vector atomic magnetometer measures the vector magnetic field near 40 000 nT， the sensitivity of measuring total fields is less than 1 nT/Hz^1/2（@0.1 Hz）， the sensitivity of measuring angles is less than 0.1°/Hz^1/2（@0.1 Hz）， and the proportion of dead zone in spatial solid angle is less than 12%. The vector magnetometer described in this article has the technical characteristics of dynamic continuous measurement， wide range and small dead zone.