The invention relates to a constructing method of a rice field roadbed, relates to a constructing method for roadbeds, and solves the technical problem that the rice field roadbed is difficult to construct. In order to solve the technical problem, the constructing method disclosed by the invention adopts the scheme of I, separately ditching drainage ditches in two sides of the slope base of the roadbed; II, draining water in a rice field within the scope of the roadbed, and eliminating silts and sundries; III, ditching pile pits in the roadbed, wherein the pile pits in two neighboring lines are mutually interlaced; IV, uniformly blending small lame blocks and crushed stones in the proportion of the small lame blocks to the crushed stones being 1:1 so as to obtain a mixture, and enabling the pile pits to be stuffed with the mixture and tamped; V, covering a layer of soil over the pile stuffed with the mixture, and stably pressing the soil with a tracked vehicle; VI, holding pile stuffed with the mixture and the soil in a sealing manner; and VII, performing rolling on the roadbed with an iron three-wheel road roller, so that roadbed earthworks can be reclaimed and constructed over the soil. Through the adoption of the construction method disclosed by the invention, the roadbed construction of the rice field can be realized, the engineering quality is also guaranteed, and the engineering cost is reduced.