The Arabidopsis mutants involved in chloroplast development were induced by seed treatment of diepoxybutane which was rarely known mutagenic compound in plant mutagenesis. Three kinds of mutants designated as iml, gev, and yev were represented by the characteristics of variegated leaves, green vein with yellow leaves, and yellow green vein with green leaves respectively. We investigated the ultrastructure of chloroplast in mutated regions using transmission electron microscopy. The ultrastructure of chroloplast in wildtype showed regularly stacked grana thylakoid and stroma thylakoid while iml, gev and yev mutants displayed different shapes of grana stacking and stroma stacking of chloroplasts. Genetic analysis of three chloroplast mutants exhibit that divergent traits were ruled by a single recessive nuclear gene.