Following the successful synthesis of single-layer metallic Janus MoSH and semiconducting MoSi2N4, we investigate the electronic and interfacial features of metal/semiconductor MoSH/MoSi2N4 van der Waals (vdW) contact. We find that the metal/semiconductor MoSH/MoSi2N4 contact forms p-type Schottky contact (p-ShC type) with small Schottky barrier (SB), suggesting that Janus MoSH can be considered as an efficient metallic contact to MoSi2N4 semiconductor with high charge injection efficiency. The electronic structure and interfacial features of the MoSH/MoSi2N4 vdW heterostructure are tunable under strain and electric fields, which give rise to the SB change and the conversion from p-ShC to n-ShC type and from ShC to Ohmic contact. These findings could provide a new pathway for the design of optoelectronic applications based on metal/semiconductor MoSH/MoSi2N4 vdW heterostructures.