The invention discloses a life evaluation method of a CFB furnace tube based on grey prediction theory. The life evaluation method helps solve the problems of hard life evaluation and the like of the current furnace tube and does not need to consider factors which thins wall thickness, such as complex wear, even corrosion and the like; and the life evaluation method has the advantages of requiring fewer raw data, convenient computation and high precision, and can be used in actual engineering practice and the like. The life evaluation method comprises the following steps: (1) measuring a set of wear data; (2) adopting the measured data and a method for weighting processing on time interval in the process of accumulating and reducing the raw data to establish an unequal time interval GM (1,1) prediction model based on the CFB furnace tube wear of the measured wearing capacity data; (3) computing the wearing capacity, that is, wall thickness reduction amount by the established prediction model; (4) comparing a computation result with a measurement result, and optimizing the model; (5) obtaining a specific prediction model of the furnace tube wall thickness reduction amount of a boiler; and (6) predicting the subsequent wear capacity according to the specific prediction model, thus computing the residual life of the furnace tube.