In view of the newly synthesized two-dimensional (2D) semiconductor material WSi₂N₄ (WSN) and the 2D metal material MoSH (MSH), a metal-semiconductor MSH/WSN Schottky-junction is constructed in this work. In practical applications of metal-semiconductor contact, the presence of the Schottky barrier degrades the device performance severely. Therefore, it is crucial to obtain a smaller Schottky barrier height or even an Ohmic contact. Here, the first-principles calculations are used to investigate the variation of the Schottky barrier in MSH/WSN Schottky-junction under an external electric field and a biaxial strain. The results show that both external electric field and biaxial strain can effectively modulate the Schottky barrier of the MSH/WSN Schottky-junction. The dynamic switching between the p-type Schottky contact and the n-type Schottky contact can be achieved under the action of positive external electric field in the MSH/WSN Schottky-junction. Under the action of negative external electric field, the MSH/WSN Schottky-junction can be modulated to realize the transition from the Schottky contact to the Ohmic contact. The large biaxial strain can also induce the MSH/WSN Schottky-junction to realize the transition between the p-type Schottky contact and the n-type Schottky contact. This work may provide theoretical guidance for the WSN semiconductor based Schottky functional devices and field-effect transistors.