The invention discloses a raw soil building material modification method, belongs to the technical field of building materials, solves the technical problem that traditional raw soil building materials have low strength, high brittleness, poor resistance to water, and the like, first the performance of a raw soil material is improved by a chemical modification agent, a modified raw soil building block is prepared by physical pressure moulding technology, the performance of the raw soil material is improved significantly, especially aiming at vast raw soil resources in urgent need of development and utilization in Northern Shaanxi area, the method can largely use local raw soil materials, is convenient in material taking, economical and practical, strong in integrity, excellent in thermal processing property, simple in operation, easy in implementation and popularization, and to be more important, in line with the requirements of green building, and broad in application prospect.