The invention provides a fused magnesite crushing and separating system which comprises a jaw crusher, a vertical shaft impact crusher, a first cyclone separator, a linear vibrating screen, a second cyclone separator and a magnetic separator, wherein an outlet of the jaw crusher is communicated with an inlet of the vertical shaft impact crusher; an outlet of the vertical shaft impact crusher is communicated with an inlet of the first cyclone separator; a discharge hole of the first cyclone separator is communicated with the linear vibrating screen; a residue outlet of the linear vibrating screen is communicated with an inlet of the second cyclone separator; and a discharge hole of the second cyclone separator is communicated with an inlet of the magnetic separator. The fused magnesite crushing and separating system has a simple, reasonable and compact structure, is good in crushing and micro powder separating effect and can effectively lower the content of micro powder in a product.