Slenderness ratio is one of the main influencing factors on the mechanical properties of laminated bamboo columns under eccentric compression. This paper presents the research results of 20 column tests. Two main failure models can be classified based on the test results for the columns. The increasing speeds for the strain value are similar for all specimens. Regardless of the length, the strain across the cross-section of the column for each specimen is basically linear throughout the loading process, following standard normal section bending theory. Relationships between the ultimate mechanical parameters and slenderness ratios are proposed, including an equation for calculating the slenderness ratio influencing coefficient, which gives good agreement with the test results. All the equations presented in this paper can be used as a reference for further work to establish a generally applicable formula for code adoption.