Abstract: In engineering materials science, it is extremely challenging to construct the relationship between the "microstructures and internal stresses" inside materials and the "macroscopic performance and service life" of components. Up to now, neutrons have been the only probe for bulk materials that allows engineers and material scientists to acquire information nondestructively about the size and density of the microstructures and three-dimensional distribution of internal stresses deep inside materials. Neutron diffraction stress analysis and small angle neutron scattering are recognized to be of essential value. This article reviews briefly the development, applications and future of these techniques. The neutron scattering instrumentation that will be completed in China in the near future will provide a platform for innovative research for multidisciplinary users,and play a lasting fundamental role in the nation's major engineering fields.