The stalk-stubble breaking and mulching process is a core technique for some conservation tillage system. Over the past 10 years, this technique has been widely adopted in the dry farming area of northern China. On the basis of analyzing the existing problems in stalk-breaking and stubble-breaking machines, we have developed a combined stalk-stubble breaking and mulching machine with two frames fixed together, the stalk and stubble-breaking blade rotors were mounted respectively on the frames. The machine can be used to break the maize ( Zea mays L.) stalk and stubble and bury about one-third of the broken stalk and stubble in the soil, preventing them being blown away by wind. This paper describes the structural features of the machine, the design of main working parts, determination of the parameters of the central position of the two blade rotors, and presents the performance test results. The tests showed that the machine had a stalk-breaking rate of 89% and the vegetation coverage rate reached 67.9%, which meets the agro-technical requirements in the dry farming area of northern China.