In order to make better use of excavator in foundation pit, a new excavator with telescopic arm is designed in this paper. The innovations mainly manifests in four aspects. First, the use of telescopic arm decreases the height for the excavation in foundation pit. Secondly, the design of truss-guide and trolley brings a high speed to excavator’s lateral move in large scale, easy for dirt shoveling in the wide foundation pit. Thirdly, the travelling system with two pails of dual-pedrail makes it possible for excavator free walking, flexible steering, and obstacle avoiding. The last but not the least, the wireless remote control technology can keep operators distant from danger and other unpleasant working conditions.