The invention relates to a testing method of the aggregating specific surface area of a bituminous mixture. The problem that in the prior art, quality cannot be guaranteed, and no methods exist for quickly and accurately testing the index of the aggregating specific surface area is solved. The testing method of the aggregating specific surface area of the bituminous mixture comprises the following steps that first, the relationship of a coating film thickness and a film coating machine working parameter is determined, namely a calibration process of the testing method of the aggregating specific surface area is carried out; second, according to the obtained relationship of the coating film thickness and the film coating machine working parameter, testing is carried out on the specific surface area of an aggregate to be tested, namely a testing process of the testing method of the aggregating specific surface area is carried out. According to the method, the specific surface area of the aggregate can be accurately tested, and the method is especially suitable for testing the specific surface area of an aggregate in an irregular shape and with complex surface lines. The method can be used for the field of building materials and the research of physical and microscopic property of irregular particles.