The invention relates to a preparation method of rare earth isoprene rubber with improved performance. A one-segment mixing, aging and two-segment mixing process is used. The method for preparing the rare earth isoprene rubber reduces the rubber plasticating and remilling process, adjusts the sequence of one-segment mixing, two-segment mixing and aging, so the mixing time is only about 450 seconds, and compared with the conventional preparation method, the mixing time is reduced by 30 to 50%. The method also has the obvious advantages of high processing efficiency, small energy consumption and easy operation. The Mooney viscosity change of the rare earth isoprene rubber is lower relative to the natural rubber and low Mooney viscosity isoprene rubber prepared by the conventional method, which indicates that the invention has weak effect on sizing material mechanical cutting and thermo-oxidative cracking damage, and is more suitable for the sizing material molding process. Simultaneously, the performance indexes of 300% stretching strength, the tensile strength, the elongation at break and the like of the vulcanizate are higher than the determined values of other rare earth isoprenerubber preparing methods.