Laser induced breakdown spectroscopy (LIBS) has become a powerful tool for the direct analysis of a large variety of materials in order to provide qualitative and/or quantitative information. However, there is a lack of information for LIBS analysis of agricultural products. In this work a LIBS system has been designed for the discrimination of Ca, Cu, Fe, and Na elements in Gannan Navel orange. An experimental setup was established by using a Nd:YAG laser operating at 1064 nm and a grating spectrometer with CCD detector. The LIBS spectra of pericarps and fleshes of Gannan Navel orange were collected. The typical spectrum lines of mineral elements Ca,Cu,Fe,and Na were chosen and identified, and the relative content of four elements in pericarps and fleshes were compared and analyzed respectively. The results showed that the relative content of elements Ca, Cu, Fe, and Na in pericarps was more than in fleshes. The LIBS relative intensity of Na, Fe, Ca, Cu elements in pericarps decreased in turn, while the LIBS relative intensity of Na, Cu, Ca, Fe elements in fleshes increased in turn. The experimental results also showed that the relative content of mineral elements in farm product may be analyzed fast by LIBS, and the LIBS technique is a novel means for rapid detection the quality of farm product.