Enhancement-mode AlGaN/GaN MOSHEMTs have been widely used in power electronic applications thanks to its superior electrical characteristics [1, 2]. Several methods have been proposed to fabricate E-mode AlGaN/GaN HEMTs like gate recess , F- doping at the AlGaN barrier layer , and p-type GaN cap layer . Nevertheless, the high threshold voltage and high output current is hard to obtain simultaneously for the E-mode AlGaN/GaN HEMT. Recently, the E-mode AlGaN/GaN MOSHEMT is realized by integrating two of the above methods to obtain higher Ids and more positive Vt [6, 7]. This work proposes gate structure engineering by integrating three processes, including gate recess, fluorine doped barrier layer and in-situ chlorine doped Al2O3 gate dielectric layer to realize the E-mode AlGaN/GaN MOSHEMT. The present MOSHEMT shows higher output current density and more positive threshold voltage than the MOSHEMTs which use gate recess and fluorine doping techniques.