A ground insert lamp includes a ground insert and a lighting assembly detachably mounted on the ground insert. The lighting assembly includes a lamp body, and a light source module. The lamp body is provided with a fixed portion movably mounted on and rotatable relative to the ground insert. The lamp body includes a primary shell, a regulating shell, and a focus regulating module. The light source module is mounted in the primary shell. The focus regulating module includes a reflective mirror, and a convex mirror. The reflective mirror is mounted on the primary shell. The convex mirror is mounted in the regulating shell. The regulating shell is moved relative to the primary shell, and the convex mirror is moved with the regulating shell.