The geometry of the spinning triangle influences the distribution of fiber tension in the spinning triangle and fiber tensile stresses within the yarn and, thus, affects the component of yarn torque due to these stresses. In this study, a modified energy approach was adopted to study the distribution of fiber tension in the staple spinning triangle. The spinning triangle had an asymmetric geometry, unlike that studied by other researchers. A shape parameter was introduced in the analysis. The principle of minimum potential energy was applied to analyze three cases, that is, spinning triangle with uniformly distributed fibers, spinning triangle with fiber substrands and spinning triangle with buckled fibers. The effects of shape of spinning triangle on the fiber tension distribution at the spinning triangle were investigated. The results showed that the tension distribution of fibers at the spinning triangle became more uniform with the increase of the symmetry of the spinning triangle. In addition, as yarn twist increased, more tension of outer fibers was created and more compressive force developed on the central fibers in the spinning triangle. Compared with fiber tension distribution at the spinning triangle without fiber buckling, the fiber tensions distributed at the spinning triangle exhibited different shapes and had lower values with fiber buckling.