Epitaxial heterostructures based on organic-inorganic hybrid perovskites and two-dimensional materials hold great promises in optoelectronics, but they have been prepared only via solid-state methods that restricted their practical applications. Herein, we report cubic-phased MAPbBr (MA=CH NH ) nanocrystals were epitaxially deposited on trigonal/hexagonal-phased MoS nanosheets in solution by facilely tuning the solvation conditions. In spite of the mismatched lattice symmetry between the square MAPbBr (001) overlayer and the hexagonal MoS (001) substrate, two different aligning directions with lattice mismatch of as small as 1% were observed based on the domainmatching epitaxy. This was realized most likely due to the flexible nature and absence of surface dangling bonds of MoS nanosheets. The formation of the epitaxial interface affords an effective energy transfer from MAPbBr to MoS , and as a result, paper-based photodetectors facilely fabricated from these solution-dispersible heterostructures showed better performance compared to those based on MoS or MAPbBr alone. In addition to the improved energy transfer and light adsorption, the use of MoS nanosheets provided flexible and continuous substrates to connect the otherwise discrete MAPbBr nanocrystals and achieved the better film forming ability. Our work suggests that the scalable preparation of heterostructures based on organic-inorganic hybrid perovskites and 2D materials via solution-phase epitaxy may bring about more opportunities for expanding their optoelectronic applications.