The invention discloses a dynamic three-dimensional measurement method and system for a single color fringe pattern. The method comprises the following steps: S1, projecting three uniform red, green and blue intensity patterns with consistent intensity; shooting a projected uniform intensity pattern, and collecting red, green and blue uniform intensity patterns; S2, calculating a coupling strength coefficient between color channels; S3, projecting a color fringe pattern to the to-be-measured object and shooting the color fringe pattern; S4, decoupling gray fringe patterns of three channels in the color fringe pattern; S5, decomposing the decoupled color fringe pattern to obtain three background-free fringe patterns and three background patterns; S6, solving a modulation degree ratio by using the background image to obtain a color-normalized background-free fringe pattern; S7, demodulating the background-free fringe pattern after color normalization, and obtaining a demodulation phase; and S8, unwrapping the demodulation phase, solving an unwrapped phase, and reconstructing a three-dimensional shape. According to the method, three gray fringe patterns are coded on one color fringe pattern, and a gray phase shift fringe pattern meeting the demodulation requirement of a phase shift method is obtained through projection and decoupling.