Abstract: A set of computerized reactor start-up equipment is developed, which consists of the detector, data acquisition circuit, computer and data process software. The data acquisition circuit is made up of plus amplifier and plus counter, multi-range-ultra-low current amplifier, analog to digital conversion circuit and data transfer circuit. This equipment can be used in the experiment of subcritical extrapolation, supercritical interpolation, value of central control rod and value of radial fuel element. A test has performed in the zero power experiment of Miniature Neutron Source Reactor with LEU, and some results have been illustrated.