Distributed video coding (DVC) is a new video coding paradigm derived from Slepian & Wolf's and Wyner & Ziv's information-theoretic results in 1970's. Turbo-code-based Wyner-Ziv codec provides a practical solution to lossy DVC schemes. It is able to provide good Rate distortion (DR) performance while shift complexity burden from encoder to decoder. In this paper, we proposed a pixel domain DVC system based on punctured turbo codes. The iterative decoding of turbo codes based on Maximum A Posterior (MAP) for DVC case is elaborated. Virtual channel model estimation is introduced to compute the a priori probabilities to be input to the turbo decoder. The experimental results presents significant gains compared to traditional intraframe coding paradigm. It is concluded that the proposed DVC system obtains better RD performance against previous similar works.