Abstract: The design methods about H-section aluminium alloy beam-columns are often applied to T-section directly， and this situation is not consistent with the stability performance of the latter． Parameter analysis based on finite element methods was executed to study the in-plane stability capacity of extruded T-section aluminium beam-columns with the tip of the web in bigger compression． The analysis methods considered the effects of material nonlinearity， geometrical nonlinearity，and initial imperfection． The calculations of three kinds of T-sections of weak hardening alloy and strong hardening alloy were done，whose results were compared with those by GB 504292007，the proposed formula and numerical methods． The results showed that GB 504292007 was safe but overabundant，and the proposed formula is safe enough and more exact than the former．