Focusing on low-frequency shaking of the construction machine cab, the article analyzes reasons of the shaking and shows several improved isolator designs to reduce the effect of shaking on drivers’ comfort. Firstly according to previous 4 modes below 26 Hz from the finite element analysis of an excavator cab with 6 cab mounts, reasons for low-frequency shaking are analyzed. Then two improved measures of isolator designs for keeping the shaking small effectively are considered. Static analysis on one silicone-oil-sealed-type rubber mount, which can improve drivers’ comfort effectively according to practical application, is done. Besides, perfect setting approaches of isolators can greatly alleviate the cab shaking, which is confirmed by finite element modal analysis of the excavator cab, the first natural frequency of cab increased to 15.55Hz from 6.91Hz.