Abstract: Red-flesh sweet pomelo is a new mutant strain.To study the sources of the variation,pollens of red-flesh sweet pomelo,Guanxi sweet pomelo and Xiahe sweet pomelo were compared.The results showed that:(a) the pollen external appearance,shape and size of the red-flesh pomelo were similar to those of Guanxi sweet pomelos;(b) there were greater differences between the red-flesh and Xiahe sweet pomelo;(c) the main aperture types of the red-flesh and Guanxi sweet pomelo were both 5 colporate and no significant difference in their perforation density,while apparent difference existed between the red-flesh and Xiahe sweet pomelo;and(d) sporopollen identification further confirmed that there was only a minute genetic distance between the red-flesh and Guanxi sweet pomelo.