Electrostatic human body detector is a detector which is able to obtain the target information through catching up the electrostatic field of the target. It plays an important role in the human body detection technology. Based on dielectrophoresis theory, the detection of the coupling heart electric field between the operator and the detected living human is focused on; in the meanwhile, the electrorotation effect involving this problem is analyzed. Firstly, the electrorotation effect, which belongs to dielectrophoresis theory, is described. Then, the double human body coupling heart electric field and the electrorotation four-pole arch electrode structure which generates detective electric field, are analyzed. Finally, the finite element method is used to simulate and calculate the detective electric field. Simulation result clearly demonstrates electrorotation effect at three special angles. The conclusion is consistent with the theory and is one of significant studies on the passive electrostatic human body detection technique.