By using the VASP, we studied the magnetic and electronic properties of the monolayer lateral hetero-junction WS2-MoS2-nanoribbons (WS2-MoS2-NRs). Our results show that the NRs’ edge chirality and width affect significantly its magnetic and electronic properties. The monolayer lateral hetero-junction ZZ-WS2-MoS2-NRs(ZZ: zigzag) exhibitmetallic behavior and have considerable magnetic moment. Their magnetic moments decrease in the order of Nz=2, 6 and 4 (the width of NRs). While, the magnetic moment decreases with the increased rz (the number of the Mo-S chains, rz≠0 and rz≠Nz) at the same width Nz. The NA-AC-WS2-NR (AC: armchair) and NA-AC-WS2-MoS2-NR-1 (the number of the Mo-S chain is 1) show metallic behavior when NA=3 (the width of NRs). The other monolayer lateral hetero-junction AC-WS2-MoS2-NRs remain the nonmagnetic and semiconductingbehavior as bulk. But they are indirect band-gap except for the NA=3, rA=2 (the number of the Mo-S chains) and NA=7, rA=0 when NA<9. However they are direct band-gap when NA≥9. Their lowest and highest band gaps are 0.150eV and 0.581eV, respectively. These unique magnetic and electronic properties will provide guidanceon the WS2-MoS2 hetero-junction application in nanodevice.