The invention relates to the field of installation of parts or accessories of a baking oven, in particular to a copper plate assembly method of a slab continuous casting machine crystallizer. The copper plate assembly method of the slab continuous casting machine crystallizer comprises the two steps of cleaning a copper plate and assembling the copper plate and is characterized in that: when the copper plate is cleaned, scale depositing on surfaces of a back plate and the copper plate (1) are removed with a scraper knife, and the surface of the back plate, the surface of the copper plate (1) and the contact surface between the back plate and the copper plate (1) are polished by using sand paper; and when the copper plate is assembled, and bolts (21) are fastened according to a sequence from the middle part to the left side and the right side in a row-by-row expanding way by using a torque wrench. The invention has short construction period, low maintenance cost, simple and effective operation and high maintenance quality.