A method for screening a treatment agent candidate for GM1 gangliosidosis comprising the following steps: A) treating differentiated neural progenitor cells (NPCs) or neurosphere from a GM1 gangliosidosis iPSCs model with the sample compound or composition, wherein, the GM1 gangliosidosis iPSCs model is characterized by the following i) ∼ vii): i) c.601C>T mutation of GLB1 gene; ii) R201C mutation of β-galactosidase (β-gal) protein; iii) normal cell morphology of iPSCs; iv) expression of pluripotency markers such as OCT4, NANOG, TRA-1-81, SSEA3, SSEA4, and TRA-1-60; v) up-regulation of GLB1 gene and β-gal protein; vi) decrease of β-gal activity; and vii) accumulation of GM1 ganglioside and lysosome, wherein the NPCs are characterised by the following a)∼h): a) expression of neural marker genes including NESTIN, NCAM, PAX6, and OTX2; b) expression of neural marker proteins including MAP2, TUJ1, and S100; c) cleaved cystic neurosphere; d) decrease of neural rosette formation; e) up-regulation of GLB 1 gene and β-gal protein; f) decrease of β-gal activity; g) accumulation of GM1 ganglioside and lysosome; and h) up-regulation of inflammation related genes. B) analyzing the characteristics of the neural progenitor cells (NPCs) or neurosphere of step A); and C) comparing the result obtained in step B) with the non-treated control group. A) treating differentiated neural progenitor cells (NPCs) or neurosphere from a GM1 gangliosidosis iPSCs model with the sample compound or composition, wherein, the GM1 gangliosidosis iPSCs model is characterized by the following i) ∼ vii): i) c.601C>T mutation of GLB1 gene; ii) R201C mutation of β-galactosidase (β-gal) protein; iii) normal cell morphology of iPSCs; iv) expression of pluripotency markers such as OCT4, NANOG, TRA-1-81, SSEA3, SSEA4, and TRA-1-60; v) up-regulation of GLB1 gene and β-gal protein; vi) decrease of β-gal activity; and vii) accumulation of GM1 ganglioside and lysosome, wherein the NPCs are characterised by the following a)∼h): a) expression of neural marker genes including NESTIN, NCAM, PAX6, and OTX2; b) expression of neural marker proteins including MAP2, TUJ1, and S100; c) cleaved cystic neurosphere; d) decrease of neural rosette formation; e) up-regulation of GLB 1 gene and β-gal protein; f) decrease of β-gal activity; g) accumulation of GM1 ganglioside and lysosome; and h) up-regulation of inflammation related genes. i) c.601C>T mutation of GLB1 gene; ii) R201C mutation of β-galactosidase (β-gal) protein; iii) normal cell morphology of iPSCs; iv) expression of pluripotency markers such as OCT4, NANOG, TRA-1-81, SSEA3, SSEA4, and TRA-1-60; v) up-regulation of GLB1 gene and β-gal protein; vi) decrease of β-gal activity; and vii) accumulation of GM1 ganglioside and lysosome, a) expression of neural marker genes including NESTIN, NCAM, PAX6, and OTX2; b) expression of neural marker proteins including MAP2, TUJ1, and S100; c) cleaved cystic neurosphere; d) decrease of neural rosette formation; e) up-regulation of GLB 1 gene and β-gal protein; f) decrease of β-gal activity; g) accumulation of GM1 ganglioside and lysosome; and h) up-regulation of inflammation related genes. B) analyzing the characteristics of the neural progenitor cells (NPCs) or neurosphere of step A); and C) comparing the result obtained in step B) with the non-treated control group.