The realization of n-type and p-type carrier conductivity by doping in semiconductor materials is of great significance in the field of semiconductor devices. Theoretically, the n-type and p-type doping efficiency of semiconductor materials can be explored by calculating charge transfer energy levels and defect formation energy. The structural, magnetic, electronic, defect formation energy and charge transfer energy levels of four potential p-type doped defects in g-AlN (BeAl, MgAl, CaAl, SrAl) were systematically calculated based on frist-principles and combined with two-dimensional (2D) charged defect calculation method.The results show that all defective systems are deep acceptor energy levels, and it is difficult to provide p-type carriers for the 2D AlN. On the contrary, they will capture the holes in AlN, which will seriously affect the hole conductivity of 2D g-AlN materials. BeAl has the minimum forming energy in the whole range of electronic chemical potential, so it is easier to be doped into g-AlN, affecting the p-type doping efficiency of g-AlN materials.