The invention provides a rubber particle weight increasing method and a preparation method of a rubber concrete. Through the rubber particle weight increasing method, the weight and the density of a rubber particle are increased, the rubber particles are more evenly distributed in the concrete, and the mechanical property of the rubber concrete is improved. The related rubber particle weight increasing method is characterized by comprising the following steps: 1, weighing a certain amount of the rubber particles, soaking with clear water until the particles completely sink down and no bubble exists on the surfaces of the particles; 2, taking out the rubber particles, adding the rubber particles into a cement paste and stirring, wherein the volume ratio of the rubber particles to the cement paste is 1:1 and 20% of a cement accelerator is doped in the cement paste; 3, observing the thickness of a mixture, adding proper amount of water until the slump constant of the mixture is 6-10, stirring for a certain period of time; 4, evenly spreading the mixture by using a shovel blade, basically separating the particles, and airing naturally; 5, screening an excessive powder by using a mesh sieve, maintaining in water for a plurality of days, and taking out; 6, stirring the rubber once every few hours, stirring for times, airing until the particles are grey white, and obtaining the weight increased rubber particles.