The invention discloses a seamless spliced moisture-proof floor and a preparation process thereof. Dense micro corrugated grooves are formed in the back surface of the seamless spliced moisture-proof floor. The periphery of the seamless spliced moisture-proof floor is coated with moisture-proof and weather-proof vegetable oil. The moisture-proof and weather-proof vegetable oil comprises stillingia oil, refined linseed oil, refined tung oil, tea seed soil and sophora oil. The weight ratio of the stillingia oil to the refined linseed oil to the refined tung oil to the tea seed soil to the sophora oil is 2:3:3:1:1. According to the seamless spliced moisture-proof floor, no gap is retained in the upper and lower portions of spliced seams of the spliced floor, back water/moisture, dust, garbage and the like can be effectively prevented from invading from gaps in the side edges of the side surfaces or the back surface, and meanwhile, the seamless spliced moisture-proof floor is good in moisture-proof and weather-proof performance and not prone to being deformed.