A theoretical scenario used for achieving efficient field-free molecular orientation with a few half-cycle pulses (HCPs) is proposed,with the LiH molecule as an example.Compared with a single HCP,three HCPs can excite more rovibrational transitions and enhance the degree of molecular orientation.By optimizing the laser parameters,a maximum value of 0.798 for the degree of molecular orientation is obtained.In recent years,manipulation of molecular alignment and orientation with ultrashort pulse laser has captured the increasing attention of researchers.Many phenomena such as photodissociation,[1] photoionization,[2,3] and photofragment analysis[4-6] are related to molecular alignment and orientation.