The invention relates to a method for regulating and controlling the particle size of an intermediate phase carbon microball efficiently. The method is characterized by comprising the following step of regulating the content of primary quinoline insolubles (QI) in raw materials so as to prepare the intermediate phase carbon microball of the required meso-position particle size (D50), wherein the raw materials are selected from any one or the combination of pitch and heavy-weight oil, and the preferably selected pitch is selected from any one or the combination of coal tar, medium-temperature coal tar pitch, secondary coal tar pitch, petroleum pitch, secondary oil heavy weight oil, anthracene oil and polyaromatic hydrocarbon. The invention also relates to complete equipment and a catalyst pretreatment device for preparing the intermediate phase carbon microball. According to the invention, the meso-position particle size of the prepared intermediate phase carbon microball through regulating the content of the primary quinoline insolubles in the raw materials, the D50 of the prepared intermediate phase carbon microball is concentrated, and the yield reduction caused by the subsequent screening can be prevented effectively, thus the yield is high, the production cost is low, and the performances of the intermediate phase carbon microball can be ensured and improved, and the defect of ignition of a mixed liquid spraying tank caused by nonuniform mixing of the catalyst and raw materials, partial overheating, over severe catalyst reaction is overcome, and the complete equipment and the catalyst pretreatment device for preparing the intermediate phase carbon microball have the advantages of simplicity in operation, no dust, low preparation cost, environment pollution prevention and the like.