Abstract: Objective To investigate the effects of heat-shock on development and accumulation of lipid and glycogen in planarian Dugesia japonica. Methods The development of planarians was evaluated by the body length and body weight. The body length, body weight, and the accumulation of lipid and glycogen in parenchymal cells were examined in heat-shock (35℃) treated planarians. The possible associations of development with lipid or glycogen storage were further analyzed in heat-shock treated planarians. Results After heat-shock treatment for different time intervals (16, 20, 24, 28, and 32-h), the body weights and body lengths of heat-shock treated planarians were all significantly decreased compared with those in control planarians without heat-shock treatment. Compared with the lipid accumulation in control planarians, heat-shock treatment resulted in the sharp decrease of lipid droplet number and the reduction of lipid droplet size in parenchymal cells. Similarly, the relative intensities of labeled signals for glycogen in parenchymal cells were significantly decreased after heat-shock treatment. Moreover, linear regression analysis suggests that both the body weight and the body length were significantly correlated with the relative size of lipid droplet and the relative intensity of glycogen signal in heat-shock treated planarians. Conclusion Treatment with the stress of heat-shock can obviously suppress the development of planarians, and the close association between the development and the accumulation of lipid or glycogen exists in heat-shock treated planarians.