The invention relates to a humidity adjusting material technical field, and particularly discloses passive composite humidity adjusting particles; humidity adjusting advantages of porous materials, high-molecular materials and inorganic salts are integrated, a foaming agent is introduced, a moisture absorption and releasing medium, a moisture storage source and a moisture storage space are combined, a composite humidity adjusting material with good humidity adjusting performance is synthesized, then a mould-resistant bacteriostatic material is added, and the composite humidity adjusting particles having humidity adjusting and mould-resistant bacteriostatic functions and having the particle size of 0.5-3.5 mm are prepared; the composite humidity adjusting particles increase a contact area of the humidity adjusting material with air, are beneficial for merging the humidity adjusting material with conventional building materials, and realize diversification applications of the humidity adjusting material.