Initial flowering date (IFD) is closely related to mature period of peanut pods. In present study, a population of recombinant inbred lines (RIL) derived from the cross between Silihong (female parent) and Jinonghei 3 (male parent) was used to map QTLs associated with IFD. The RIL population and its two parental cultivars were planted in two locations of Hebei Province, China from 2015 to 2018 (eight environments). Based on a high-density genetic linkage map (including 2996 SNP and 330 SSR markers) previously constructed in our laboratory, QTLs were analyzed using phenotypic data and the best linear unbiased prediction (BLUP) value of initial flowering date by inclusive composite interval mapping (ICIM) method. Interaction effects between every two QTLs and between individual QTL and environment were also analyzed. In cultivated peanut, IFD was affected by genotypic factor and environments simultaneously, and its broad sense heritability (h2) was estimated as 86.8％. Using the IFD phenotypic data from the eight environments, a total of 19 QTLs for IFD were detected, and the phenotypic variation explained (PVE) by each QTL ranged from 1.15 to 21.82％. Especially, five of them were also detected by the BLUP value of IFD. In addition, 12 additive QTLs and 35 pairs of epistatic QTLs (62 loci involved) were identified by the joint analysis of IFD across eight environments. Three QTLs (qIFDB04.1, qIFDB07.1 and qIFDB08.1) located on chromosome B04, B07 and B08 were identified as main-effect QTL for IFD, which had the most potential to be used in peanut breeding. This study would be helpful for the early-maturity and adaptability breeding in cultivated peanut.