The selection principle of ready-mixed mortar is that the use of wet-mixed or dry-mixed masonry mortar is determined by the situation of project and surrounding suppliers of ready-mixed mortar. If wet-mixed masonry mortar is selected for use, then the consistency and water retention of wet-mixed mortar should be determined by the types of block materials; the setting time, whether 8h, 12h or 24h, should be determined by the construction progress, construction plan and suppliers’ delivery time of wet-mixed mortar. Similarly, if dry-mixed masonry mortar is selected, the variety of dry-mixed masonry mortar should also be determined by the type of block materials. Since dry-mixed mortar has a wider selection range of raw materials than wet-mixed mortar does, it can produce special mortar, with varieties more targeted. Therefore, dry-mixed masonry mortar is a development direction of ready-mixed mortar.