In this paper, the geometric structures, band structures and transport properties of the armchair silicene nanoribbon with or without vacancy defect and Co/Ni-vacancy complex defects have been investigated by using first-principles calculations. The calculated results show that the atoms near the defect appear the restructuring, and it can be found that the introduced defect can modulate the electronic properties of armchair silicene nanoribbon. The defective sub-bands are good for the electronic transport of armchair silicene nanoribbon with Co-vacancycomplex defect but not good for armchair silicene nanoribbon with Ni-vacancy complex defect. Interestingly, the armchair silicene nanoribbon with Co-vacancy complex defect has negative differential conductance, which is in accordance with the total transmission of armchair silicene nanoribbon. It is suggested that the calculated results should be good for designing the electronic device based on armchair silicene nanoribbon.