People need efficient, convenient and safe security inspection technology urgently, as the contradiction between modern security inspection technology and health privacy issues becomes more prominent. This article first introduces the principle of terahertz non-imaging spectral detection technology, proposes the technical indicators of the terahertz spectral detection system suitable for security applications, and then designs an optical system based on ZEMAX that matches the technical indicators, and uses non-sequential mode to simulate and Evaluation, finally based on ProE, completed the design of the compact detection system structure with the optical system, and realized the handheld application of the detection system.