In this paper, a model is developed to provide flow curves of pure Al at a wide range of temperatures and strain rates. The calculations are based on the dislocation evolution during deformation in the sense of the three internal state variables approach. The model treats dislocations as being either mobile or immobile inside the subgrains or as dislocations that are arrested and stored in the cell walls between the subgrains. Generation and annihilation of dislocations due to different factors are considered and analyzed in our work and for each factor, a particular parameter is introduced. For calibration of these parameters, experimental flow curves for pure Al are taken as the basis. Compression tests are performed at temperatures from -150°C to 500°C with the strain rate of 1/s, 0.1/s and 0.01/s. The model is implemented in the MatCalc software. The effect of temperature and strain rate on each state parameter is illustrated and discussed.