The invention relates to the field of mechanical structures, in particular to an anti-theft guard bar switch with a tension spring and a manufacturing method of the anti-theft guard bar switch. The anti-theft guard bar switch comprises a shell, a zipper, the tension spring and alarm equipment. The shell is rectangular, and mounting convex points and mounting holes are formed in the shell. The tension spring, the zipper, the alarm equipment and a contact switch of the alarm equipment are arranged in the shell. When the zipper is pulled by external force, the contact switch of the alarm equipment sends alarm signals to the alarm equipment connected with the contact switch. When external force is removed, the tension spring shrinks inwards to reset, and the contact switch resets and is in a standby mode. Guard bar switches are mounted on a wall on the left side of a window and a wall on the right side of the window, an alarm host connected with the alarm equipment can give out alarm information according to set alarm programs, the internet of things can be formed through a communication network, and therefore remote control is achieved.