Objective To establish a simple, fast, wide linear range, accurate and sensitive method for the determination of urea in swimming pool water. Methods According to Examination Methods for Public Places-Part 2: Chemical Pollutants (GB/T 18204. 2-2014) (hereinafter referred to as the national standard method), the water bath time, types and concentrations of reagents, standard series, etc. were optimized. The urea content in swimming pool water was measured by using spectrophotometer for methodological evaluation. Results The concentration range of improved national standard method (referred to as the improved method) was 0-3.50 mg/L, the correlation coefficient was 0.999 8, the relative standard deviation (RSD, n=6) was 1.17%-4.75%, the recovery rate was 97.61%-103.06%, and the detection limit of the method was 0.082 mg/L. There was no statistically significant difference between the improved method and the national standard method for measuring the urea content in 43 swimming pool water samples (Z=‒0.013, P=0.990). Conclusion Improved method has high precision and accuracy, wide linear range, short heating time, stable color products, and is suitable for quantitative detection of urea in swimming pool water.