As the obliquity of Mars is strongly chaotic, it is not possible to give a solution for its evolution over more than a few million of years. Using the most recent data for the rotational state of Mars, and a new numerical integration of the Solar System, we provide here a precise solution for the evolution of Mars spin over 10 to 20 Myr.Over 250 Myr, we present a statistical study of its possible evolution, when considering the uncertainties in the present rotational state. Over much longer time span, reaching 5 Gyr, the chaotic diffusion prevails, and we have performed an extensive statistical analysis of the orbital and rotational evolution of Mars, relying on Laskar's secular solution of the Solar System, based on more than 600 orbital and 200 000 obliquity solutions over 5 Gyr.The density function of the eccentricity and obliquity are explicited with simple analytical formulas.We found an averaged eccentricity of Mars over 5 Gyr of e=0.0690 with standard deviation s_e=0.0299, while the averaged value of the obliquity is 37.62 deg with a standard deviation of 13.82 deg and a maximal value of 82.035 deg.We find that the probability for Mars obliquity to have reached more than 60 degin the past 1 Gyr is 63.0%, and 89.3% in 3 Gyr. Over 4 Gyr, the position of Mars axis is given by a uniform distribution on a spherical cap limited by the obliquity 58.62 deg, with the addition of a random noise allowing a slow diffusion beyond this limit. We can also define a standard model of Mars insolation parameters over 4 Gyr with the most probable values for the eccentricity 0.068 and 41.80 deg for the obliquity.