A comparative study between Sm12Co59Cu6Fe20Zr3 master alloy magnet and melt-spun ribbon magnet is made by applying the same traditional sintering-solid solution-aging-slow cooling method. The X-ray diffractometer, electron microscope and magnetometer are employed to investigate the structure and magnetic properties of the magnets. It is found that two types of sintered magnets are formed both of which have Th2Zn17-type main phase. Master alloy sintered magnet has a typical cellular structure, with average cell size of 88.3nm and cell wall width less than 20nm, and the comprehensive magnetic properties are: Hci=21.1kOe, Mr=75.9emu/g and Ms9T=107.8emu/g. The coercivity of the ribbons melt-spun at a speed of 20m/s is merely 2.1kOe, while in ribbon sintered magnet, this value can approach as high as 27.4kOe, together with remanence 61.8emu/g and maximum magnetization Ms9T=103.6emu/g. A typical cellular–lamellar microstructure is obtained in ribbon sintered magnet, with average cell size of 102.3nm, cell wall width less than 10nm and lamellar size of 1–3nm. The high-coercivity of ribbon sintered magnet can be attributed to the following factors: the existence of lamellar phases, larger cell size, thinner cell walls, more cell boundary phases and desirable composition distribution.