By assembling two isolated monolayers, the vertical stacking heterostructure of SnSe2/MoSe2 is designed. The morphology of the SnSe2/MoSe2 vertical heterostructures is observed by optical microscope and atomic force microscope. Furthermore, through controlling different annealing time at the temperature 150 degrees C, the promoted field-effect performance of the SnSe2/MoSe2 heterostructures is observed. The underlying mechanism can be attributed to the increasing interlayer coupling along with the extended annealing time. On the other hand, due to the type-II band alignment, the electron will transfer from the MoSe2 to SnSe2, leading to the weaker photoluminescence intensity. The results show that the field-effect performance can be greatly improved via appropriate annealing time, exhibiting great potential application of the SnSe2/MoSe2 heterostructure in optoelectronic devices. (C) 2017 Elsevier B.V. All rights reserved.