Abstract: The smoothed particle hydrodynamics (SPH), as a Lagrange meshless particle method, has been successfully adopted to solve various types of coupling problems. Based on the SPH method, a moisture-heat coupling problem in two-dimensional domain with a circular localized heat source is solved, the shortcomings of the existing particle arrangement scheme are revealed at the preprocessing stage in program. According to the specific problem, a new particle arrangement scheme is proposed to compensate for the loss of accuracy in numerical calculation process, where the radial particle spacing exactly equals and the circumferential spacing is roughly equal to the radial one. The analysis of mathematical properties of the moisture-heat coupling equation shows that the SPH algorithm can be used for the numerical simulation of this type of coupled problem. Finally, the program based on the SPH algorithm is worked out to solve the moisture-heat coupling problem of an unsaturated soil with localized heat source, and the heat transfer and moisture migration regularity in the unsaturated soil medium are analyzed.