As a common stem vegetable in daily life, potatoes not only contain rich carbohydrates but also contain minerals, lutein and other active substances beneficial to human health. Studies on the nutrients and solanine contained in the skin, flesh and sprout of potatoes are of great significance for food safety and potato quality assessment. First, the spectra of skin, flesh and sprout of potatoes are obtained by laser-induced breakdown spectroscopy (LIBS), and the nutrient elements and solanine in different parts of potatoes are analyzed. Second, the difference in spectral peak intensity between metallic and non-metallic elements in different parts of the potatoes is observed. Finally, the reason for the difference is discussed in terms of the local thermal equilibrium condition and the ratio of ion to atom densities by the calculation of the temperature and electron density of the laser-induced plasma. Results show that LIBS is a reliable and effective in situ and online test methods for the analysis of various elements in different potato parts.