Several kinds of evaluation methods for the uncertainty in coordinate measurement are introduced and it points out that most of these methods are failed to the uncertainty evaluation for special objectives because of lack of theory support or practicability. Therefore, this paper investigates the uncertainty evaluation of gear measurement with Coordinate Measurement Machines (CMMs) by the Monte Carlo method. Firstly, a measuring model is established based on the files for the calibration and compensation of the specific CMM, then the mode is used to obtain measuring results with a large number of sample points. Using these simulated results, the uncertainties can be evaluated more conveniently. Finally,the Monte Carlo method is successfully used in evaluating measurement uncertainty of gear profiles and obtained stable results show that the maximal difference among the results is less than 0.03 μm when the typical uncertainty is 0.96 μm. The paper suggests that Monte Carlo method can support specific uncertainty measurement and can change the situation that common evaluation method can not be suitable for the commercial CMMs.