Abstract: To satisfy the progressive requirements of test, a neutron standard test beam based on the reactor neutron source China Mianyang Research Reactor(CMRR) was proposed, and its conceptual design is shown in the paper. This instrument would be used to test the performance of components designed for spectrometer and develop some quantitative analysis of special materials. At first, it was simulated by VITESS software. Then some adjustment about its physical parameter was optimized based on the simulation results. In this system, the monochoromator was designed with vertical focusing function which could provide neutrons with continuous wavelength (0.1-0.3 nm). Between the monitor and the slit, the collimator was removable. While it is removed, the neutron flux at sample stage was up to 6.15106 n/(cm2s). With the collimater, the neutron flux at sample stage was reduced to 2.07106 n/(cm2s), but the resolution of NSTB was up to 0.2%.