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Cytidine triphosphate synthase (CTPS) forms cytoophidia in all three domains of life. Here we focus on the function of cytoophidia in cell proliferation using <i>Schizosaccharomyces pombe</i> as a model system. We find that converting His³⁵⁹ of CTPS into Ala³⁵⁹ leads to cytoophidium disassembly. By reducing the level of CTPS protein or specific mutation, the loss of cytoophidia prolongs the G2 phase and expands cell size. In addition, the loss-filament mutant of CTPS leads to a decrease in the expression of genes related to G2/M transition and cell growth, including histone chaperone <i>slm9</i>. The overexpression of <i>slm9</i> alleviates the G2 phase elongation and cell size enlargement induced by CTPS loss-filament mutants. Overall, our results connect cytoophidia with cell cycle and cell size control in <i>Schizosaccharomyces pombe</i>.