Abstract: The paper introduces the methods of target thickness and uniformity measure-ments including weighing, α-particle thickness gauge, quartz thickness gauge,optical transmittance and Rutherford backscattering. An α-particle gauging whichmeasures target thicknesses up to several μm is metioned. A fast tickness measure-ments for C, Au and Cu targets by spectrophotometer are given. A high sensitivequartz gauge which can measure minimum deposit of 0.04μg/cm~2 is described.Thickness and impurity determinations by RBS with accuracy better than 5% aresummarized.