Ficus species (figs) and their pollinating wasps (fig wasps) comprise obligate mutualisms with high specificity, and such tight interspecific interactions are widely considered as a key driving factor for the diversification in both mutualists. Host identification of fig wasps predominantly relies on chemical communications, but it is still unclear how chemical communications stabilize fig-fig wasp mutualisms and facilitate co-diversification. Here, we reviewed the relevant studies to summarize the basis of chemical communications between figs and fig wasps and the mechanisms underlying the specific host identification. We then elucidated the crucial contribution of chemical communications to the maintenance of fig-fig wasp mutualisms at both species and population levels, with further discussion on how chemical communications mediated speciation through co-speciation and speciation by host-shifts of fig wasps. Finally, we addressed the necessity of combining physiological and multi-omics technologies in future research on fig-fig wasp mutualisms, which offered expectations for revealing coevolutionary mechanisms in other plant-insect interactions and their potential responses to the ongoing global changes.