With the development of neural networks in recent years, a variety of photoelectric neural network frameworks have been successively proposed and presented strong application potentials in image and language processing and so on. A new type of optical scattering neural network based on transparent medium imaging is designed. Firstly a physical characteristic of the bidirectional propagation in scattering medium is presented, a single layer intelligent unit of optical neural network is formulated by cascading a stack of medium layer, and the nonlinear photoelectric material film is appended to act as nonlinear activation response. Then, the corresponding digital bidirectional complex-valued neural network is established according to the bidirectional scattering physical model, and the backpropagation algorithm for its digital weight update is derived. The weight parameters of a digital complex-valued neural network can be realized by adjusting the physical parameters of scattering medium. The numerical experiments about the effectiveness of the intelligent classification of proposed optical scattering neural network is verified on the MNIST data set.