The invention relates to in-situ preparation of a cobalt-base alloy gradient coating on an aldary surface through laser induction and a method thereof, and belongs to the material technical field. The gradient coating comprises a first coating, a second coating and a third coating, and the thickness of each coating is 0.04 to 0.10mm, 0.03 to 0.08mm and 0.07 to 0.13mm respectively. The preparation method comprises the steps as follows: the aldary surface is processed through activating treatment, Al, Co, C, Ni, Cr, Fe, Si, CrO3, Y2O3, Mo, W, MgO, B2O3 and graphite nodule milling are mixed and are prepared into a mixed materiel for the three coatings respectively; and the mixed materiel for the three coatings is spread on the aldary surface; and the ceramic particle reinforced cobalt-base alloy gradient coating is prepared through laser induction in-situ. The invention adopts the advanced technology for preparing an advanced heatproof wear-resistant gradient coating on the aldary surface, and has good application prospect and important economic significance.