[Objectives]  To investigate the effect of adding folic acid to the larval diet of Apis mellifera ligustica on DNA methylation and female development. [Methods]  Two-day-old female A. m. ligustica larvae were randomly selected from sister colonies and divided into six equal-sized groups. The control group (CK) was fed a diet without additional folic acid, whereas the remaining five groups were fed the same diet with the addition of either 0.02%, 0.04%, 0.06%, 0.08% or 0.10% folic acid. Larvae were reared at room temperature of (34.5 ± 0.5) ℃ at a relative humidity of 90% ± 5% until they emerged. Indices of folic acid metabolism and DNA methylation related indices were measured in 3- to 5-day-old larvae, and the developmental duration and weight of newly emerged bees was recorded. [Results]  (1) The 0.04% treatment group had significantly higher levels of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF) than the control group at 3, 4 and 5 days of age (P < 0.05). This group also had significantly higher expression of the dihydrofolate reductase (DHFR) gene, the serine hydroxymethyltransferase (SHMT) gene and the methylenetetrahydrofolate reductase (MTHFR) gene (P < 0.05), and significantly higher MTHFR enzyme activity (P < 0.05), in the larval period. (2) This treatment group also had significantly higher expression of the DNA methyltransferase 1a (Dnmt1a) gene in 3-day-old larvae (P < 0.05), and significantly higher DNA methyltransferase 1 (DNMT1) enzyme activity in 3- and 4-day-old larvae, than the control group (P < 0.05). The 0.04% treatment group had significantly lower DNA methyltransferase 3 (DNMT3) enzyme activity in 3-day-old larvae compared to the control group (P < 0.05), and significantly lower Dnmt3 gene expression and DNMT3 enzyme activity in 4-day-old larvae (P < 0.05). The level of DNA methylation in this treatment group was also significantly lower in 4-day-old bees (P < 0.05). (3) The average developmental duration (19.95 d) of the 0.04% treatment group was significantly lower (P < 0.05), and the average weight (0.17 g) of newly emerged bees was, significantly higher, than that of the control group (P < 0.05). [Conclusion]  The addition of 0.04% folic acid to the larval diet can reduce DNA methylation in 4-day-old A. m. ligustica larvae, shorten developmental duration and increase the weight of newly emerged bees. The addition of 0.04% folic acid to the larval diet helps female A. m. ligustica larvae develop into Queens.