Detection system makes the core equipment for collecting feature information of radiation fields, and is the key point and technical basis for carrying out pulsed radiation detection. Its performance directly determines the choice of measuring method and the quality of measured data. A systematic description of characteristic parameters affecting its performance in pulsed radiation detection is the basis for the design, development, application and comprehensive performance assessment of the detection system. Main parameters of detection systems for measuring time spectrum and intensity of mixed pulsed neutron/gamma radiation fields include detection sensitivity, time response, energy response, linear current and discrimination of neutron to gamma rays, etc. To realize these parameters in designing a detection system, certain detection construction and technical principles have to be established in accordance with the basic interaction principles of neutron/gamma rays with materials. Designing principles include balancing energy collection with charge collection, geometry efficiency with high signal-noise ratio, separation of signal response from irradiation response, detection sensitivity with time response, overall performance with application reliability, etc. The designing technology of radiation detection systems can be developed with an integrated utilization of these principles.