As a new-style structural material, aluminium alloy fits the need of development of modern engineering structures to long-span, lightweight and high-durability. Lags of research restrict the application and development of aluminium structures in our country, and it is urgent to study the aluminium structures more widely and to draw the design criterions concerned. Supporting by projects of , this paper presents the study on in-plane and out-plane stability capacity of aluminium beam-columns.Firstly, based on experimental research, the constitutive relation models of aluminium material were studied and chosen, and the finite element model was established and confirmed. Secondly, based on parameter analysis, the basic forms of the interaction expressions for calculating the stability capacity of aluminium beam-columns were chosen, and several adjust coefficients within the expressions were confirmed. Finally, a series of design formulas were proposed. The main productions of this paper can be found in the following list:1) Stability tests were made on eccentrically loaded extruded H-section aluminium columns. The main parameters varied in the tests are slenderness ratio and load eccentricity ratio. All 19 specimens tested failed by overall flexural buckling or lateral-torsional buckling. The influences of buckling behaviors and above parameters to stability capacity and deformation performance were examined.2) When aluminium beam-columns occur flexural buckling or lateral-torsional buckling, analytical methods can give the approximate results of actual stability capacity, which have been verified by comparison with the experimental results.3) Ansys software was adopted to calculate the stability capacity of aluminium beam-columns, calculation results of which have been verified by comparison with the experimental results. So the finite element model can fit the need of the study.4) Systemic analysis was executed to several constitutive relation models of aluminium material. Verified by comparison with the experimental results,