To provide a method for producing a dispersion liquid of a nanoparticle composite, in which a nano-sized particulate composite is uniformly dispersed in a high concentration and the dispersion stability is superior.

The method for producing the dispersion liquid of a nanoparticle composite includes processes 1 to 4. The process 1 is a dispersion process for forming a nanoparticle dispersion by dispersing microparticles in a first solvent, using a block copolymer, as a dispersion stabilizer, in which a specified amino group contained in the copolymer and an organic acid compound having a polymerizable group form a salt. The process 2 is a dilution process for diluting the nanoparticle dispersion with a second solvent having a boiling point different from that of the first solvent. The process 3 is a composite forming process for forming the nanoparticle composite by crosslinking the block copolymer. The process 4 is a concentration process for concentrating the dispersion liquid by distilling out the first or second solvent of the nanoparticle composite.