Using the relative proper motions and membership probabilities of 785 stars in the region of the open cluster M 11 (within 25 of the cluster center), we found for the cluster, a distance of 1659 pc, and an age of (1.8 - 2.2) 10 8 yr, a radius of about 24.5 pc, a luminosity mass of 4354 M , and a virial mass of 5000 M . A method is proposed to derive the present-day luminosity function from the observed luminosity function. Our analysis shows that, as an open cluster of intermediate age, the cluster stars show quite a clear mass segregation effect in space and that while mass segregation in the velocities does exist, it is not so obvious.