Pure aluminium thin films were deposited on stainless and mild steel substrates through rf magnetron sputtering at rf powers of 150 and 200 W. Surface analysis of the films was undertaken using atomic force microscopy. The surface structure evolution, roughness and distribution were examined and discussed. Power spectral density, skewness and Kurtosis parameters were used to explain the nature and distribution of the surface structures on the thin aluminium films as reported from the line profile analyses. The result shows that the morphologies of the surface structures of Al thin films vary with power and substrate type. The coatings also exhibited higher roughness at the power of 200 W. A strong link exists between the atomic force microscopy (AFM) observations and scanning electron microscopy (SEM) analysis, which implies that AFM can be considerably used to study the microstructural evolution of thin films prepared by magnetron sputtering.