Urea is the final product of amino acid metabolism and is widely used in agriculture as a nitrogen fertilizer. However, when the concentration of urea accumulates to a certain value in the human body, it will cause certain damage to the organs of the human body. Therefore, it is of great significance to establish a simple and sensitive method for urea detection. Resonance Rayleigh Scattering (RRS) is a molecular spectroscopy technique with simple operation, good sensitivity and low energy consumption. It has been widely used in the fields of chemistry and life sciences. At present, the application of the resonance Rayleigh scattering technique to the quantitative analysis of urea has also been reported, but there are still problems such as complicated operation and low sensitivity. In this paper, a simple, rapid and sensitive resonant Rayleigh scattering-energy transfer (RRS-ET) method is developed for the detection of trace urea (UR) in human urine. In the presence of HCl and the stabilizer thiosemicarbazone (TSC), dimethylglyoxime (DMG) can react with UR to form a stable red diazine derivative of 4,5-dimethyl-2-imidazolidone (DIK). The RRS-ET phenomenon occurs between DIK as an energy acceptor and an energy donor polystyrene nanoprobe (PS), which causes the RRS signal of the system to change. Within a certain range, as the UR concentration increases, the RRS intensity at 500 nm decreases linearly. In order to achieve the best detection results, the factors affecting the system signal are optimized. The results show that when the concentration of HCl solution is 0.75 mol·L^-1, the concentration of TSC solution is 0.22 mmol·L^-1, the concentration of DMG solution is 19.35 mmol·L^-1, the concentration of PS is 17.5 μg·mL^-1, the temperature of the water bath is 80 ℃, and the bath time is 20 min, the system obtains the best detection effect. Under the optimal conditions, the resonance Rayleigh scattering signal reduction value of the polystyrene nanoparticle system is linear with the UR concentration in the range of 2.0~3 200 ng·mL^-1, and the detection limit is 2.0 ng·mL^-1. At the same time, the effect of coexisting substances on the determination of 2 000 ng·mL^-1 UR is investigated. The results show that 100 μg·mL^-1 of Na⁺, Zn²⁺, 20 μg·mL^-1 of Mn²⁺, Cr³⁺, 10 μg·mL^-1 of SO^2-₄, NO₃^- Co²⁺, Fe³⁺, 2 μg·mL^-1 Cr⁶⁺ and Ca²⁺ did not interfere with UR determination. The results show that the method has good selectivity. Finally, the RRS-ET method is applied to the determination of UR in the urine. The recovery of the spiked samples is 94.19%~96.94%, and the relative standard deviation (RSD) is 4.20%~6.35%. The test results are satisfactory. Based on this, a new method of resonance Rayleigh scattering-energy transfer analysis of urea is established with simple operation and high sensitivity.