Based on radial profiles, disk can be divided into three categories:Type I, classical single exponential (10%); Type II, down-bending joint exponential (60%); Type III, up-bending joint exponential (30%). Milky Way is the benchmark for the research of the disk Galaxy formation and evolution! And the outer disks of galaxies present a unique laboratory for studying the process of disk formation and it can provide us with a direct view of disk assembly in progress. I will introduce my recent work about the milky way outer disk. And some highlights about our group works with LAMOST data will also be mentioned.