The invention provides a prestretching type mechanical environment simulator which comprises a base, a self-locking device, a boundary condition simulation device, a strain simulation device, a top support and a marine acoustic material, wherein the boundary condition simulation device comprises a boundary hydraulic cylinder, a boundary connecting rod for connecting the boundary hydraulic cylinder, and a clamp; the strain simulation device comprises a stain hydraulic cylinder and a stain connecting rod for connecting the stain hydraulic cylinder; the stain hydraulic cylinder is fixed on the base; the boundary hydraulic cylinder is installed on the base through the self-locking device; the top support is connected with the strain connecting rod; a clamping structure is formed by the marine acoustic material, the boundary condition simulation device and the top support; the upper part of the clamping structure is formed by the marine acoustic material; the lower part of the clamping structure is formed by the other components; and a tested piece is arranged between the upper part and the lower part of the clamping structure and is fixed by the clamp. The simulator has the characteristics of being simple in structure, convenient to install, easy to operate and control and the like.