To achieve fast nondestructive detection of drugs, the optical system of infrared spectroscopy detection based on Fourier transform is designed. The operating band of system ranges from 4000 cm－1 to 12000 cm－1. The suitable optical structure is designed and characteristic parameters of the optical components are determined. Ray tracing and optimization analysis on optical system designed are carried out with ZEMAX. The experimental platform is set up, and the near-infrared spectral data of five similar drugs are collected. The data are processed by combining principal component analysis (PCA) with error back propagation artificial neural network (BPANN). The spectra of five drugs are effectively identified and the recognition accuracy ratio reaches 93.333%. Experimental results show that the near-infrared spectroscopy detection system is suitable for non-destructive analysis of drugs, and can effectively identify similar drugs.