AbstractTurbulent mixing with a single second‐order isothermal reaction in a homogeneous flow is considered. A mixing model is stated using the probability density function (PDF) equation method and the concepts of mixture fraction and progress variable. Different micromixing models are compared. With the interaction exchange mean/linear square mean estimation (IEM/LSME) model, the time variation of the mixture fraction PDF contradicts the physical representation of mixing. The Langevin model describes mixing from the segregating state to the homogeneous state of a mixture. The PDF model proves to be two‐mode at intermediate mixing stages. This is also true for the multi‐zone PDF model. As compared to the multi‐zone PDF model, others reveal higher averaged progress variables over the entire time range and at all Damköhler number values. Such a difference is made by the approximations for the averaged reaction rate that should be allowed for in the modeling of turbulent mixing with chemical reaction.