Flowering is a crucial step for the transition from vegetative to reproductive growth in plant’ s life cycle. The character of early-flowering and early-maturing of oilseed rape is the key to solve the conflict between oilseed rape and other summer crops in the multiple-cropping system. Identification of early-flowering oilseed rape and dissecting the basis of early-flowering are conducive to accelerating the procedures of molecular breeding of early-maturing varieties. A novel and stably inherited very-early-flowering oilseed rape Yingchun Yi Hao was evaluated for flowering characteristics in the present study， with 15 sowing stages distributed in nine different months. The results showed that Yingchun Yi Hao sown in the different dates successfully flowered， and unlike common spring type oilseed rapes， was not demanding of low temperature for vernalization. Compared with early-flowering semi-winter line FM4 and late-flowering semi-winter line FM5， Yingchun Yi Hao sown in semiwinter ecological environments in October more rapidly entered the flowering stage， and also was superior in cold tolerance and in general agronomic traits. The molecular experiment revealed that six copies of vernalization key gene BnaFLC on chromosomes A02， A03， C02 and C03 synchronously down-regulated the expression in Yingchun Yi Hao grown in high temperature environment during the vegetative growth stage. 50× whole genome sequencing was performed for‘ Yingchun Yi Hao’ and two reference samples， line FM4 and FM5， which identified 16229 SNPs and 5842 INDELs correlated to 1064 flowering time genes in Brassica napus， and screened out 69 SNPs and 34 INDELs that caused the variation of flowering time genes encoding proteins specific to Yingchun Yi Hao， including 14 SNPs and 4 INDELs that showed positive regulation with BnaFLC， and 11 genes were deduced to be candidate genes for very-early-flowering of‘ Yingchun Yi Hao’ . These genes， except BnaFLC itself， are located upstream of BnaFLC and positively regulate the expression of BnaFLC.