In this paper, a new type of linearly polarized wiggler, its the magnetic field amplitude and peri-od of which can be varied conveniently, has been investigated in detail. The wiggler consists of many loops which separately arrange on the wiggler framework. Varying the radius and period, we can ob-tain the field profile as was expected. The theory about the magnetic field profile in the wiggler has been derived and results of computer simulation show that it can produce any magnetic field profile that we desire by following methods:a)variation of loop radius only;b)variation of the wiggler period only;c) variation of the both.